The Project Gutenberg eBook, Vegetable Teratology, by Maxwell T. Masters, Illustrated by E. M. Williams This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org Title: Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Author: Maxwell T. Masters Release Date: November 6, 2007 [eBook #23354] Language: English Character set encoding: ISO-8859-1 ***START OF THE PROJECT GUTENBERG EBOOK VEGETABLE TERATOLOGY*** E-text prepared by Charlene Taylor, Leonard Johnson, and the Project Gutenberg Online Distributed Proofreading Team (http://www.pgdp.net) Note: Project Gutenberg also has an HTML version of this file which includes the original illustrations. See 23354-h.htm or 23354-h.zip: (http://www.gutenberg.net/dirs/2/3/3/5/23354/23354-h/23354-h.htm) or (http://www.gutenberg.net/dirs/2/3/3/5/23354/23354-h.zip) Transcriber's note: Words enclosed between equal signs were in bold face (=bold=). A list of corrections is at the end of the book. The Ray Society. Instituted MDCCCXLIV. [Illustration] _This volume is issued to the Subscribers to the_ RAY SOCIETY _for the Year_ 1868. London: MDCCCLXIX. VEGETABLE TERATOLOGY, An Account of the Principal Deviations from the Usual Construction of Plants by MAXWELL T. MASTERS, M.D., F.L.S. With Numerous Illustrations by E. M. Williams. London: Published for the Ray Society by Robert Hardwicke, 192. Piccadilly. MDCCCLXIX. TO JOSEPH DALTON HOOKER, M.D., D.C.L., LL.D., F.R.S., F.L.S., ETC. ETC. DIRECTOR OF THE ROYAL GARDENS, KEW, This Volume IS GRATEFULLY INSCRIBED. TABLE OF CONTENTS. PAGE INTRODUCTION xxi BOOK I. DEVIATIONS FROM ORDINARY ARRANGEMENT 1 PART I.--UNION OF ORGANS 8 CHAPTER I. COHESION 9 Cohesion between axes of same plant, 9--Fasciation, 11--Cohesion of foliar organs, 21--Of margins of single organs, 21--Tubular petals, 23--Cohesion of several organs by their margins, 25--Of the sepals, 27--Of the petals, 28--Of the stamens, 29--Of the pistils, 29--Ascidia or pitchers, 30. CHAPTER II. ADHESION 32 Adhesion of foliar organs, 32--Of leaves by their surfaces, 33--Of foliar to axile organs, 34--Of sepals to petals, 34--Of stamens to petals, 34--Of stamens to pistils, 35--Miscellaneous adhesions, 35--Of fruit to branch, 36--Synanthy, 36--Syncarpy, 45--Synspermy, 50--Between axes of different plants of same species, 50--And of different species, 55--Synophty. PART II.--INDEPENDENCE OF ORGANS 58 CHAPTER I. FISSION 59 Fission of axile organs, 60--Of foliar organs, 61--Of petals, 66--Of stamens, 68--Of carpels, 68. CHAPTER II. DIALYSIS 69 Dialysis of margins of individual parts, 70--Of margins of parts of same whorl-calyx, 70--Of corolla, 71--Of stamens, 73--Of carpels, 73. CHAPTER III. SOLUTION 76 Solution of calyx from ovary, 77--Of stamens from petals, 82. PART III.--ALTERATIONS OF POSITION 83 CHAPTER I. DISPLACEMENT 84 Displacement of bulbs, 84--Of inflorescence, 85--Of leaves, 87--Of parts of flowers, 91--Of carpels, 96--Of placentas and ovules, 96. CHAPTER II. PROLIFICATION 100 Prolification of the inflorescence, 102--Median foliar, 103--Median floral, 105--Lateral foliar, 106--Lateral floral, 107--Prolification of the flower, 115--Median foliar, 116--Median floral, 119--Axillary prolification, 138--Foliar, 141--Floral, 142--Complicated prolification, 151--Of embryo, 155. CHAPTER III. HETEROTAXY 156 Formation of adventitious roots, 156--Of shoots below the cotyledons, 161--Adventitious leaves, 162--On scapes, 163--Production of leaves or scales in place of flower-buds, 164--Viviparous plants, 168--Formation of buds on leaves, 170--In pith, 171--On bulbs, 172--Production of gemmæ in place of spores, 173--Of flowers on leaves, 174--Of flower-buds in place of leaf-buds, 176--Of flowers on spines, 177--Of flower-buds on petals, 177--On fruits, 178--In ovaries, 180--Of stamens in ovaries, 182--Of pollen in ovules, 185--Homomorphic flowers of Compositæ, 188--Heterotaxy affecting the inflorescence, 188--Supra-soriferous ferns, 190. CHAPTER IV. HETEROGAMY 190 Change in the position of male and female flowers, 191--From monoecious to dioecious condition, 193--From dioecious to monoecious, 193--From hermaphroditism to unisexuality, 195--From unisexuality to hermaphroditism, 197--Pollen replaced by ovules, 201. CHAPTER V. ALTERATIONS IN THE DIRECTION OF ORGANS 201 Fastigiation, 202--Eversion, 204--Altered direction of leaves, 205--Altered direction of flower, 206--Reflexion, 209--Gymnaxony, 211. BOOK II. DEVIATIONS FROM ORDINARY FORM 213 PART I.--STASIMORPHY 216 CHAPTER I. PERSISTENCE OF JUVENILE FORMS 217 Stasimorphy in leaves of Conifers, 217--Regular peloria, 219. PART II.--PLEIOMORPHY 228 CHAPTER I. IRREGULAR PELORIA 228 PART III.--METAMORPHY 240 CHAPTER I. PHYLLODY 241 Phyllody of bracts, 242--In inflorescence of Conifers, 245--Of calyx, 245--Of corolla, 251--Of stamens, 253--Of pistils, 256--Of ovules, 262--Changes in nucleus of ovule, 269--Phyllody of accessory organs, 272--Chloranthy, 273--General remarks on, 278. CHAPTER II. METAMORPHY OF FLORAL ORGANS 281 Sepalody of petals, 282--Petalody of calyx, calycanthemy, 283--Petalody of stamens, 285--Of anther, 291--Of connective, 293--Compound stamens, 294--Petalody of pistils, 296--Of ovules, 297--Of accessory organs, 297--Staminody of the bracts, 298--Of sepals and petals, 298--Of pistils, 299--Of accessory organs, 301--Pistillody of perianth, 302--Of sepals, 302--Of stamens, 303--Of ovules, 310. PART IV.--HETEROMORPHY 311 CHAPTER I. DEFORMITIES 311 Formation of tubes, 312--In flower, 314--Spurs, 315--Contortion, 316--Spiral torsion, 319--Of leaf, 326--Adventitious tendrils, 326--Interrupted growth, 327--Cornute leaves, 328--Flattening, 328. CHAPTER II. POLYMORPHY 329 Heterophylly, 330--Dimorphism, 333--Sports or bud-variations, 336. CHAPTER III. ALTERATIONS OF COLOUR 337 Albinism, 337--Virescence, 338--Chromatism, 339. BOOK III. DEVIATIONS FROM ORDINARY NUMBER 340 PART I.--INCREASED NUMBER OF ORGANS 343 CHAPTER I. MULTIPLICATION OF AXILE ORGANS--INFLORESCENCE 346 Multiplication of branches, 346--Plica, 346--Polyclady, 347--Multiplication of branches of inflorescence, 348--Of bulbs, 350--Of florets, 351. CHAPTER II. MULTIPLICATION OF FOLIAR ORGANS 352 Pleiophylly, 353--Multiplication of stipules, bracts, &c., 357--Polyphylly, 358--Increased number of leaves in a whorl, 358--Polyphylly of bracts, 358--Of calyx, 358--Of corolla, 359--Of androecium, 361--Of gynoecium, 363--Of flower in general, 365--Increased number of ovules and seeds, 367--Of embryos, 369--Of cotyledons, 370--Pleiotaxy, or multiplication of whorls, 371--Pleiotaxy of bracts, 371--Of calyx, 374--Of perianth, 375--Of corolla (hose in hose), 376--Androecium, 379--Androecium of Orchids, 380--Pleiotaxy of gynoecium, 388--Increased number of flowers in an inflorescence, 391. PART II.--DIMINISHED NUMBER OF ORGANS 392 CHAPTER I. SUPPRESSION OF AXILE ORGANS 393 Acaulosia, 393--Non-development of peduncle, 393--Nature of calyx-tube (Casimir de Candolle), 394--Suppression of columella, 395. CHAPTER II. SUPPRESSION OF FOLIAR ORGANS 395 Aphylly, 395--Meiophylly, 396--Of calyx or perianth, 396--Of corolla, 397--Of androecium, 398--Of gynoecium, 399--Of flower, 400--Meiotaxy, 403--Of calyx, 403--Of corolla, 403--Of androecium, 405--Of gynoecium, 406--Of ovules or seeds, 407--Of flower, 408--General remarks on suppression, 409. BOOK IV. DEVIATIONS FROM ORDINARY SIZE AND CONSISTENCE 413 PART I--HYPERTROPHY 416 CHAPTER I. ENLARGEMENT 417 Of axile organs, 418--Knaurs, 419--Enlargement of buds, 420--Of flower-stalk, 421--In pears, 423--Of placenta, 424--Of leaves, 426--Development of parts usually abortive, 427--Enlargement of perianth, 428--Of androecium, 430--Of gynoecium, 430--Of fruit, 431--Alterations of consistence, 432. CHAPTER II. ELONGATION 488 Elongation of root, 434--Of inflorescence, 434--Of flower-stalks, 435--Of leaves, 437--Of parts of flower, 438--Of thalamus and placenta, 440--Apostasis, 440. CHAPTER III. ENATION 443 Excrescences from axile organs, warts, 444--Enation from leaves, 445--From sepals, 448--From petals, 448--Catacorolla, 451--Enation from stamens, 453--From carpels, 453. PART II.--ATROPHY 454 CHAPTER I. ABORTION 455 Abortion of axile organs, 455--Of receptacle, 457--Of leaves, 458--Of perianth, calyx, and corolla, 460--Of stamens, 463--Of pollen, 463--Of pistil, fruit, &c., 464--Of ovules, 466--Depauperated ferns, 466--General remarks, 467. CHAPTER II. DEGENERATION 470 Formation of scales, 470--Of hairs, 472--Of glands, 473--Of tendrils, 473. GENERAL CONCLUSIONS. General morphology of the leaf and axis, 476.--Homology, 476--Special morphology, 479--Calyx-tube, 480--Androecium, 482--Inferior ovary, 482--Placentation, 483--Structure of the ovule, 484--Leaves of Conifers, 484--Relative position of organs, 484--Law of alternation, 485--Co-relation, 486--Compensation, 488--Teratology and classification, 488. APPENDIX. Double flowers, varieties of, 491--Causes of production, 491--Relation to variegated foliage, 497--List of plants producing, 499. NOTE 508 INDEX TO SUBJECTS 511 INDEX OF NAMES OF PLANTS 517 LIST OF ILLUSTRATIONS. FIG. PAGE 1. Diagram of regular pentamerous flower 4 2. Cohesion of branch _Dipsacus sylvestris_ 10 3. Fasciated lettuce ('Gard. Chron.') 11 4. Fasciation in _Asparagus_ 12 5. Fasciation in _Pinus Pinaster_ 13 6. Fasciation and spiral torsion in _Asparagus_ ('Gard. Chron.') 14 7. Fasciation in scape of dandelion 16 8. Pitcher on leaf of _Pelargonium_ 22 9. Transition from flat to tubular segments of the perianth in _Eranthis_ 24 10. Pitcher of _Crassula arborescens_ (C. Morren) 26 11. Gamopetalous corolla, _Papaver bracteatum_ 28 12. Adhesion of petaloid stamen to segment of perianth, _Crocus_ 35 13. Adhesion of petal, stamen and carpel, _Cheiranthus Cheiri_ 36 14. Synanthy. _Campanula Medium_ ('Gard. Chron.') 37 15, 16. Synanthic flowers of _Calanthe vestita_ 39 17. Synanthy in _Digitalis purpurea_ ('Gard. Chron.') 40 18. Synanthy in _Calceolaria_ 41 19, 20. Syncarpic apples 47 21. Adhesion of two stems of oak ('Gard. Chron.') 51 22. Adhesion of branches of elm ('Gard. Chron.') 52 23. Adhesion of two roots of carrot, one white, the other red ('Gard. Chron.') 53 24. Section through inverted and adherent mushrooms 54 25. Bifurcated male catkin, _Cedrus Libani_ 61 26. Bifurcated leaf, _Lamium album_ 62 27. Bifurcated leaf, _Pelargonium_ 63 28. Bifurcated frond, _Scolopendrium_ 64 29. Three-lobed lip of _Oncidium_ 68 30. Dialysis of corolla in _Correa_ 71 31. Dialysis of corolla in _Campanula_ (De Candolle) 72 32. Anomalous form of orange 74 33, 34. Disjoined carpels of orange (Maout) 75 35. Proliferous rose (Bell Salter) 78 36, 37. Apple flower, with detached calyx, &c. 79 38. Flower of _OEnanthe crocata_, with detached calyx, &c. 80 39. Anomalous bulbs of tulip 85 40. Displaced leaf of _Gesnera_ (C. Morren) 88 41. Leaves of _Pinus pinea_ 89 42. Deranged leaves of yew 90 43. Cohesion of sepals and displacement of parts of _Oncidium cucullatum_ 92 44. Malformed flower of _Cypripedium_ 93 45. Diagram of the same 93 46. Diagram of natural structure in _Cypripedium_ 93 47. Diagram of malformed flower of _Lycaste Skinneri_ 93 48. Diagram of malformed flower of _Dendrobium nobile_ 94 49. Natural arrangement in same flower 94 50. Diagram of malformed violet 94 51. Monstrous flower of _Cerastium_ ('Gard. Chron.') 97 52. Inflorescence of _Polyanthus_, with tufts of leaves at the summit 105 53. Lateral prolification in inflorescence of _Pelargonium_ 108 54. Paniculate inflorescence of _Plantago major_ 109 55. Branched spike and leafy bracts of the same 110 56. Inflorescence of _Plantago lanceolata_, with leaves and secondary flower-stalks at its summit 111 57. Branched inflorescence of _Reseda Luteola_ 112 58. Thalamus of strawberry prolonged into a leafy branch ('American Agriculturist') 116 59. Flower of _Verbascum_, with dialysis of calyx and corolla and prolonged thalamus 116 60. Median floral prolification of _Dianthus_ 120 61. Leafy carpels and prolification of _Daucus Carota_ 123 62. Median floral prolification of _Delphinium_ 126 63. Median prolification, &c., of _Orchis pyramidalis_ 128 64. Proliferous rose (Bell Salter) 130 65. Axillary floral prolification of _Nymphæa Lotus_ ('Gard. Chron.') 144 66. Axillary floral prolification of _Dianthus_ 146 67. Proliferous rose 151 68. Proliferous rose ('Gard. Chron.') 152 69. Diagram of prolified orchid 153 70. Diagram of prolified orchis 154 71. Adventitious roots from petiole of celery 158 72. Germinating plant of mango 159 73, 74. Adventitious roots from leaves 160 75. Hip of rose bearing leaf 162 76. Leaves proceeding from the ovary of _Nymphæa_ sp. 162 77. Flower-stalk of dandelion, with leaves 163 78. Tuft of leaves in place of flowers in _Valeriana_ sp. 165 79. Scale-bearing spikelets of _Willdenovia_ 167 80. "Rose Willow" 167 81. Viviparous flowers of _Aira vivipara_ 169 82. Formation of shoot on leaf of _Episcia bicolor_ 171 83. Adventitious buds on root of sea-kale 172 84, 85. Production of adventitious bulbs in hyacinth ('Gard. Chron.') 172 86. Adventitious buds on hyacinth ('Gard. Chron ') 173 87-92. Nepaul barley 174, 175 93. Formation of buds on fruit of _Opuntia_ 179 94. Flower-bud in the pod of _Sinapis_ 181 94*, 95. Adventitious pod in silique of _Cheiranthus_ 182 96, 97. Grapes, with adventitious fruits in interior 183 98. Stamens in ovary of _Bæckea diosmifolia_ 184 99. Pollen in ovule of passion flower (S. J. Salter) 185 100. Female flowers at the summit of the inflorescence of _Carex acuta_ 192 101. Monoecious hop ('Gard. Chron.') 193 102. Superior ovary, &c, of fuchsia 198 103. Hermaphrodite flower of _Carica_ 199 104. Ovuliferous anthers of _Cucurbita_ sp. 200 105, 106. Prolonged inflorescence of fig 205 107. Hollow turnip, with inverted leaves 206 108. Normal flower of _Gloxinia_ 207 109. Regular peloria of _Gloxinia_ 207 110, 111. Structural details of erect _Gloxinia_ 208 112. Reflected corolla of azalea 209 113, 114. Enlarged and erect placenta of _Cuphea miniata_ (C. Morren) 210 115. Dimorphic leaves of _Juniperus sinensis_ 217 116. Regular peloria of _Delphinium_ 219 117. Structural details of the preceding 219 118. Regular peloria of violet 220 119. Double-flowered regular violet 220 120. Regular peloria of _Eccremocarpus scaber_ 222 121. Regular peloria of _Cattleya_ 223 122. Peloria of _Calceolaria_ 230 123. Peloric flower of _Aristolochia_ 232 124, 125. Peloric flowers of _Corydalis_ 236 126. Rose plantain 242 127. Leafy bracts in _Plantago major_ 243 128. Leafy scales of _Dahlia_ 244 129. Leafy sepals of rose 246 130. Leafy sepals of Fuchsia ('Gard. Chron.') 247 131. Leafy calyx of primrose 248 132. Leafy calyx of melon 248 133. Leafy sepals and petals of _Geranium_ 251 134. Leafy stamens of _Petunia_ 254 135, 136. Leafy anthers of _Jatropha_ (Müller) 255 137. Proliferous rose, with leafy carpels, &c. (Bell Salter) 257 138. Cucumber, with adventitious leaf attached (S. J. Salter) 258 139. Leafy carpels in flower of _Triumfetta_ 260 140. Leafy ovules of _Sinapis_ 264 141, 142. Leafy ovules of _Trifolium repens_ (Caspary) 265 143. Portion of leafy carpel of _Delphinium_, with ovules (Cramer) 266 144, 145. Enlarged view of section of leafy carpel, &c., of _Delphinium_ (Cramer) 267 146. Placentæ of _Dianthus_, bearing ovules and carpels ('Gard. Chron.') 268 147. Ovules passing into carpels, _Dianthus_ ('Gard. Chron.') 268 148. Leafy shoot in place of ovule of _Gaillardia_ 270 149, 150. Leafy sepals, petals, &c., of _Epilobium_ 273 151. Leafy carpel of rose, with deformed ovules 274 152. Flower of St. Valery apple 282 153. Petaloid calyx of _Mimulus_ 284 154. Double stellate columbine 287 155. Four-winged filaments of Rhododendron 290 156. Diagram of malformed flower of _Catasetum_ 291 157. Petaloid stamen of _Viola_ 292 158. Double columbine 293 159. Petaloid stamens of _Hibiscus_ 293 160. Displaced coloured leaf, &c., of tulip 302 161. Supernumerary carpels in orange (Maout) 303 162. Pistilloid stamens of poppy 304 163. Pistilloid stamens of wallflower, &c. 306 164. Passage of stamen to carpel in lily 307 165. Transition of stamens to carpels, _Sempervivum tectorum_ 309 166. Ascidia of cabbage 312 167. Stalked pitcher on lettuce leaf 313 168. Tubular petal of _Primula sinensis_ 315 169. Spurs on flower of _Calceolaria_ 316 170. Contorted stem of _Juncus_ 317 171. Contorted branch of _Cratægus_ 317 172. Spirally-twisted stem of teazel 321 173. Spirally-twisted stem _Galium_ 323 174. Spirally-twisted root ('Gard. Chron.') 324 175. Interrupted growth of radish (American Agriculturist) 327 176. Interrupted growth in apple 327 177. Polymorphous leaves of lilac 331 178. Adventitious growth on frond of _Pteris quadriaurita_ 333 179, 180. Coloured flower-stalks of feather hyacinth (C. Morren) 347, 348 181. Multiplication of catkins, _Corylus_ 349 182. Branched inflorescence of broccoli ('Gard. Chron.') 351 183, 184. Supernumerary leaf of elm 353, 354 185. Supernumerary leaf of hazel 355 186. Multiplication of parts of flower in a plum ('Gard. Chron.') 366 187. Wheat-ear carnation 372 188. Multiplication of bracts in _Delphinium Consolida_ 373 189. Multiplication of bracts in _Pelargonium_ 373 190. Double white lily 376 191. Double flower of _Campanula rotundifolia_ 378 192. Diagram of usual arrangement of parts in _Orchis_ (Darwin) 381 193. Diagram of malformed flower of _Ophrys aranifera_ 385 194. Malformed flower of _Ophrys aranifera_ 385 195. Diagram of malformed flower of _Orchis mascula_ (Cramer) 386 196. Multiplication of carpels, Tulip 388 197. Section of St. Valery apple 388 198. Regular dimerous flower of _Calanthe vestita_ 402 199. Regular dimerous flower of _Odontoglossum Alexandræ_ 402 200. Hypertrophied branch of _Pelargonium_ 418 201. Tubers in the axils of leaves of the potato 420 202. Hypertrophied pedicels of ash 421 203, 204. Hypertrophy and elongation of flower-stalk, &c., in pears 422, 423 205. Hypertrophied perianth, _Cocos nucifera_ 428 206. Elongation of flower-stalk, _Ranunculus acris_ 436 207. Linear leaf-lobes of parsley 438 208. Passage of pinnate to palmate leaves in horse-chestnut 439 209. Elongation of thalamus, apostasis, &c., in flower of _Delphinium_ (Cramer) 441 210. Adventitious growths from cabbage leaf 445 211. Crested fronds of _Nephrodium molle_ 447 212. Supernumerary petals, &c., _Datura fastuosa_ 450 213. Supernumerary petaloid segments in flower of _Gloxinia_ 451 214. Catacorolla of _Gloxinia_ (E. Morren) 452 215. Atrophied leaves of cabbage 460 216. Abortion of petals, pansy 461 217. Flower of _Oncidium abortivum_ 462 218. Bladder plum 464 INTRODUCTION. Till within a comparatively recent period but little study was given to exceptional formations. They were considered as monsters to be shunned, as lawless deviations from the ordinary rule, unworthy the attention of botanists, or at best as objects of mere curiosity. By those whose notions of structure and conformation did not extend beyond the details necessary to distinguish one species from another, or to describe the salient features of a plant in technical language; whose acquaintance with botanical science might almost be said to consist in the conventional application of a number of arbitrary terms, or in the recollection of a number of names, teratology was regarded as a chaos whose meaningless confusion it were vain to attempt to render intelligible,--as a barren field not worth the labour of tillage. The older botanists, it is true, often made them the basis of satirical allusions to the political or religious questions of the day, especially about the time of the Reformation, and the artists drew largely upon their polemical sympathies in their representations of these anomalies. Linnæus treated of them to some extent in his 'Philosophia,' but it is mainly to Angustin Pyramus De Candolle that the credit is due of calling attention to the importance of vegetable teratology. This great botanist, not only indirectly, but from his personal research into the nature of monstrosities, did more than any of his predecessors to rescue them from the utter disregard, or at best the contemptuous indifference, of the majority of botanists. De Candolle gave a special impetus to morphology in general by giving in his adhesion to the morphological hypotheses of Goethe. These were no mere figments of the poet's imagination, as they were to a large extent based on the actual investigation of normal and abnormal organisation by Goethe both alone, and also in conjunction with Batsch and Jaeger. De Candolle's example was contagious. Scarcely a botanist of any eminence since his time but has contributed his quota to the records of vegetable teratology, in proof of which the names of Humboldt, Robert Brown, the De Jussieus, the Saint Hilaires, of Moquin-Tandon, of Lindley, and many others, not to mention botanists still living, may be cited. To students and amateurs the subject seems always to have presented special attractions, probably from the singularity of the appearances presented, and from the fact that in many cases the examination of individual instances of malformation can be carried on, to a large extent, without the lengthened or continuous investigation and critical comparative study required by other departments of botanical science. Be this as it may, teratology owes a very large number of its records to this class of observers. While the number of scattered papers on vegetable teratology in various European languages is so great as to preclude the possibility of collating them all, there is no general treatise on the subject in the English language, with the exception of Hopkirk's 'Flora Anomala,' a book now rarely met with, and withal very imperfect; and this notwithstanding that Robert Brown early lent his sanction to the doctrines of Goethe, and himself illustrated them by teratological observations. In France, besides important papers of Turpin, Geoffroy de Saint Hilaire, Brongniart, Kirschleger and others, to which frequent allusion is made in the following pages, there is the classic work of Moquin-Tandon, which was translated into German by Schauer. Germany has also given us the monographs of Batsch, Jæger, Roeper, Engelmann, Schimper, Braun, Fleischer, Wigand, and many others. Switzerland has furnished the treatises of the De Candolles, and of Cramer; Belgium, those of Morren, &c., all of which, as well as many others that might be mentioned, are, with the exception of Moquin-Tandon's 'Eléments,' to be considered as referring to limited portions only and not to the whole subject.[1] In the compilation of the present volume great use has been made of the facts recorded in the works just cited, and especially in those of Moquin-Tandon, Engelmann, and Morren. A very large number of communications on teratological subjects in the various European scientific publications have also been laid under contribution. In most cases reference has been given to, and due acknowledgment made of, the sources whence information has been gathered. Should any such reference be omitted, the neglect must be attributed to inadvertence, not to design. In selecting illustrations from the immense number of recorded facts, the principle followed has been to choose those which seemed either intrinsically the most important, or those which are recorded with the most care. In addition to these public sources of information, the author has availed himself of every opportunity that has offered itself of examining cases of unusual conformation in plants. For many such opportunities the author has to thank his friends and correspondents. Nor has he less reason to be grateful for the suggestions that they have made, and the information they have supplied. In particular the writer is desirous of acknowledging his obligations to the Society, under whose auspices this work is published, and to Mr. S. J. Salter, to whom the book in some degree owes its origin. The drawings, where not otherwise stated, have been executed either from the author's own rough sketches, or from the actual specimens, by Mr. E. M. Williams. A large number of woodcuts have also been kindly placed at the disposal of the author by the proprietors of the 'Gardeners' Chronicle.'[2] As it is impossible to frame any but a purely arbitrary definition of teratology or to trace the limits between variation and malformation, it may suffice to say that vegetable teratology comprises the history of the irregularities of growth and development in plants, and of the causes producing them. These irregularities differ from variations mainly in their wider deviation from the customary structure, in their more frequent and more obvious dependence on external causes rather than on inherent tendency, in their more sudden appearance, and lastly in their smaller liability to be transmitted by inheritance. What may be termed normal morphology includes the study of the form, arrangement, size and other characteristic attributes of the several parts of plants, their internal structure, and the precise relation one form bears to another. In order the more thoroughly to investigate these matters it is necessary to consider the mode of growth, and specially the plan of evolution or development of each organ. This is the more needful owing to the common origin of things ultimately very different one from the other, and to the presence of organs which, in the adult state, are identical or nearly so in aspect, but which nevertheless are very unlike in the early stages of their existence.[3] Following Goethe, these changes in the course of development are sometimes called metamorphoses. In this way Agardh[4] admits three kinds of metamorphosis, which he characterises as: 1st. Successive metamorphoses, or those changes in the course of evolution which each individual organ undergoes in its passage from the embryonic to the adult condition, or from the simple and incomplete to the complex and perfect. 2. Ascending metamorphoses, including those changes of form manifested in the same adult organism by the several parts of which it consists--those parts being typically identical or homologous, such as the parts of the flower, or, in animals, the vertebræ, &c. 3. Collateral metamorphoses, comprising those permutations of form and function manifested in homologous organs in the different groups of organisms, classes, orders, genera, species, &c. Thus, in the first instance, we have a comparative examination of the form of each or any separate part of the same individual at different epochs in its life-history; in the second we have a similar comparison instituted between the several parts of the same organism which originally were identical in appearance, but which have in course of evolution altered in character. In the third form we have the comparative view not of one organ at different times, nor of the several parts of one organism, but of the constituent elements pertaining to those aggregates of individuals to which naturalists apply the terms classes, orders, &c. In successive metamorphosis we have a measure of the amount of change and of the perfection of structure to which each separate organ attains. In ascending metamorphosis we have a gauge of the extent of alteration that may take place in the several homologous organs under existing circumstances. In collateral metamorphosis, in the same way, we have an illustration of the degree of change possible in aggregates of organisms under existing circumstances. Now it is clear that from an investigation of all three classes just mentioned, we shall be able to gain an idea of those points which are common to all parts, to all individuals or to all aggregates, and those that are peculiar to some of them, and, by eliminating the one from the other, we shall arrive at conclusions which will be more or less generally accurate or applicable, according to the ability of the student and the extent to which the comparative analysis is earned. It is thus that morphologists have been enabled to frame types or standards of reference, and systematists to collocate the organisms they deal with into groups. These standards and groups are more or less artificial (none can be entirely natural) in proportion to the amount of knowledge possessed by their framers, and the use they make of it. From this point of view teratological metamorphosis of all three kinds demands as much attention as that which is called normal. We can have no thorough knowledge of an organ, of an individual which is an aggregate of organs, or of an aggregate of individuals of whatever degree, unless we know approximately, at least, what are the limits of each. It is not possible to trace these limits accurately in the case of natural science, but the larger our knowledge and the wider our generalisations, the closer will be our approach to the truth. The most satisfactory classification of malformations would be one founded upon the nature of the causes inducing the several changes. Thus, in all organised beings, there is a process of growth, mere increase in bulk as it were, and a process of evolution or metamorphosis, in accordance with which certain parts assume a different form from the rest, in order the better to fit them for the performance of different offices. Should growth and development be uniform and regular, that is in accordance with what is habitual in any particular species, there is no monstrosity, but if either growth or development be in any way irregular, malformation results. Hence, theoretically, the best way of grouping cases of malformation would be according as they are the consequences of:--1st. Arrest of Growth; 2ndly. Excessive Growth; 3rdly. Arrest of Development; 4thly, of Excessive or Irregular Development. In practice, however, there are so many objections to this plan that it has not been found practicable to carry it out. The inability arises to a great extent from our ignorance of what should be attributed to arrest of growth, what to excess of development, and so on. Moreover, a student with a malformed plant before him must necessarily ascertain in what way it is malformed before he can understand how it became so, and for this purpose any scheme that will enable him readily to detect the kind of monstrosity he is examining, even though it be confessedly artificial and imperfect will be better than a more philosophical arrangement which circumstances prevent him from employing. The plan followed in this volume is a slight modification of that adopted by Moquin-Tandon, and with several additions. In it the aim is to place before the student certain salient and easily recognisable points by reference to which the desired information can readily be found. Under each subdivision will be found general explanatory remarks, illustrative details, and usually a summary of the more important facts and the inferences to be derived from them. Bibliographical references and lists of the plants most frequently affected with particular malformations are also given. In reference to both these points it must be remembered that absolute completeness is not aimed at; had such fullness of detail been possible of attainment it would have necessitated for its publication a much larger volume than the present.[5] It is hoped that both the lists of books and of plants are sufficiently full for all general purposes.[6] In the enumeration of plants affected with various malformations the ! denotes that the writer has himself seen examples of the deviation in question in the particular plant named, while the prefix of the * indicates that the malformation occurs with special frequency in the particular plant to which the sign is attached. Teratological alterations are rarely isolated phenomena, far more generally they are associated with other and often compensatory changes. Hence it is often necessary, in studying any given malformation, to refer to two or more subdivisions, and in this way a certain amount of repetition becomes unavoidable. The details of the several cases of malformation given in these pages are generally arranged according to their apparent degree of importance. Thus, in a case of prolification associated with multiplication of the petals, the former change is a greater deviation from the customary form than the latter, hence reference should be made, in the first instance, to the sections treating on prolification, and afterwards to those on multiplication. To facilitate such research, numerous cross references are supplied. In the investigation of teratological phenomena constant reference must be made to the normal condition, and _vice versâ_, else neither the one nor the other can be thoroughly understood. It cannot, however, be overlooked that the form and arrangement called normal are often merely those which are the most common, while the abnormal or unusual arrangement is often more in consonance with that considered to be typical than the ordinary one. Thus, too, it is often found that the structural arrangements, which in one flower are normal, are in another abnormal, in so far that they are not usual in that particular instance. For purposes of reference, a standard of comparison is required; and this standard, so long as its nature is not overlooked, may, indeed must be, to some extent, an arbitrary one. Thus in the phanerogamous plants there is assumed to exist, in all cases, an axis (stem, branches, roots, thalamus, &c.), bearing leaves and flowers. These latter consist of four whorls, calyx, corolla, stamens, and pistils, each whorl consisting of so many separate pieces in determinate position and numbers, and of regular proportionate size. A very close approach to such a flower occurs normally in _Limnanthes_ and _Crassula_, and, indeed, in a large proportion of all flowers in an early stage of development. To a standard type, such as just mentioned, all the varied forms that are met with, either in normal or abnormal morphology, may be referred by bearing in mind the different modifications and adaptations that the organs have to undergo in the course of their development. Some parts after a time may cease to grow, others may grow in an inordinate degree, and so on; and thus, great as may be the ultimate divergences from the assumed standard, they may all readily be explained by the operation, simply or conjointly, of some of the four principal causes of malformation before alluded to. The fact that so many and such varied changes can thus readily be explained is not only a matter of convenience, but may be taken as evidence that the standard of reference is not wholly arbitrary and artificial, but that it is a close approximation to the truth. It has already been said that an arrangement like that here considered as typical is natural to some flowers in their adult state, and to a vast number in their immature condition. It would be no extravagant hypothesis to surmise that this was the primitive structure of the flower in the higher plants. Variations from it may have arisen in course of time, owing to the action of an inherent tendency to vary, or from external circumstances and varied requirements which may have induced corresponding adaptations, and which may have been transmitted in accordance with the principle of hereditary transmission. This hypothesis necessarily implies a prior simplicity of organisation, of which, indeed, there is sufficient proof; many cases of malformation can thus be considered as so many reversions to the ancestral form. Thus, teratology often serves as an aid in the study of morphology in general, and also in that of special groups of plants, and hence may even be of assistance in the determination of affinities. In any case the data supplied by teratology require to be used with caution and in conjunction with those derived from the study of development and from analogy. It is even possible that some malformations, especially when they acquire a permanent nature and become capable of reproducing themselves by seed, may be the starting-point of new species, as they assuredly are of new races, and between a race and a species he would be a bold man who would undertake to draw a hard and fast line.[7] Discredit has been cast on teratology because it has been incautiously used. At one time it was made to prove almost everything; what wonder that by some, now-a-days, it is held to prove nothing. True the evidence it affords is sometimes negative, often conflicting, but it is so rather from imperfect interpretation than from any intrinsic worthlessness. If misused the fault lies with the disciple, not with Nature. Teratology as a guide to the solution of morphological problems has been especially disparaged in contrast with organogeny, but unfairly so. There is no reason to exalt or to disparage either at the expense of the other. Both should receive the attention they demand. The study of development shows the primitive condition and gradual evolution of parts in any given individual or species; it carries us back some stages further in the history of particular organisms, but so also does teratology. Many cases of arrest of development show the mode of growth and evolution more distinctly, and with much greater ease to the observer, than does the investigation of the evolution of organs under natural circumstances. Organogeny by no means necessarily, or always, gives us an insight into the principles regulating the construction of flowers in general. It gives us no archetype except in those comparatively rare cases where primordial symmetry and regularity exist. When an explanation of the irregularity of development in these early stages of the plant's history is required, recourse must be had to the inferences and deductions drawn from teratological investigations and from the comparative study of allied forms precisely as in the case of adult flowers. The study of development is of the highest importance in the examination of plants as individuals, but in regard to comparative anatomy and morphology, and specially in its relation to the study of vegetable homology it has no superiority over teratology. Those who hold the contrary opinion do so, apparently, because they overlook the fact that there is no distinction, save of degree, to be drawn between the laws regulating normal organisation, and those by which so-called abnormal formations are regulated. It is sometimes said, and not wholly without truth, that teratology, as it stands at present, is little more than a record of facts, but in proportion as the laws that regulate normal growth are better understood, so will the knowledge of those that govern the so-called monstrous formations increase. Sufficient has been already said to prove that there is no intrinsic difference between the laws of growth in the two cases. As our knowledge increases we shall be enabled to ascertain approximately of what extent of variation a given form is capable, under given conditions, and to refer all formations now considered anomalous to a few well-defined forms. Already teratology has done much towards showing the erroneous nature of many morphological statements that still pass current in our text-books, though their fallacy has been demonstrated again and again. Thus organs are said to be fused which were never separate, disjunctions and separations are assigned to parts that were never joined, adhesions and cohesions are spoken of in cases where, from the nature of things, neither adhesion nor cohesion could have existed. Some organs are said to be atrophied which were never larger and more fully developed than they now are, and so on. So long as these expressions are used in a merely conventional sense and for purposes of artificial classification or convenience, well and good, but let us not delude ourselves that we are thus contributing to the philosophical study either of the conformation of plants or of the affinities existing between them. What hope is there that we shall ever gain clear conceptions as to the former, as long as we tie ourselves down to formulas which are the expressions of facts as they appear to be, rather than as they really are? What chance is there of our attaining to comprehensive and accurate views of the genealogy and affinities of plants as long as we are restricted by false notions as to the conformation and mutual relation of their parts?[8] That teratology may serve the purposes of systematic botany to a greater extent than might at first be supposed becomes obvious from a consideration of such facts as are mentioned under the head of Peloria, while the presence of rudimentary organs, or the occasional appearance of additional parts, or other changes, may, and often do, afford a clue to the relationship existing between plants--a relationship that might otherwise be unsuspected. So, too, some of the alterations met with appear susceptible of no other explanations than that they are reversions to some pre-existing form, or, at any rate, that they are manifestations of a phase of the plant affected different from that which is habitual, and due, as it were, to a sort of allotropism. The mutations and perversions of form, associated as they commonly are with corresponding changes of function, show the connection between teratology and physiology--a connection which is seen to be the more intimate when viewed in the light afforded by the writings and experiments of Gærtner, Sprengel, and St. Hilaire, and, in our own times, especially by the writings and experiments of Mr. Darwin, whose works on the 'Origin of Species,' and particularly on the 'Variation of Animals and Plants under Domestication' comprise so large a collection of facts for the use of students in most departments of biology. It will suffice to allude, in support of these statements, to the writings of Mr. Darwin on such subjects as rudimentary organs, the use or disuse of certain parts according to circumstances, the frequently observed tendency of some flowers to become structurally unisexual, the liability of other flowers perfectly organised to become functionally imperfect, at least so far as any reciprocal action of the organs of the same flower is concerned, reversions, classification, general morphology, and other subjects handled at once with such comprehensive breadth and minute accuracy of detail by our great physiologist. In the following pages alterations of function, unless attended by corresponding alterations of form, are either only incidentally alluded to, or are wholly passed over; such, for instance, as alterations in the period of flowering, in the duration of the several organs, and so forth.[9] Pathological changes, lesions caused by insect puncture or other causes, also find no place in this book, unless the changes are of such a character as to admit of definite comparison with normal conformation. Usually such changes are entirely heteromorphous, and, as it were, foreign to the natural organisation. The practical applications of teratology deserve the attention of those cultivators who are concerned in the embellishment of our gardens and the supply of our tables. The florist lays down a certain arbitrary standard of perfection, and attempts to make flowers conform to that model. Whether it be in good taste or not to value all flowers, in proportion as they accord with an artificial and comparatively inelastic standard of this kind, we need not stop to enquire; suffice it to say, that taking the matter in its broadest sense, the aim of the florist is to produce large, symmetrical flowers, brightly and purely coloured, or if parti-coloured, the colours must be distinct, harmonious, or contrasted. When all this is done, the flower, in most instances, becomes 'monstrous' of the eyes in the botanist, though all the more interesting to the student of morphology on that account. In like manner the double flowers, the "breaks," the "sports" which the florist cultivates so anxiously, are all of them greater or less deviations from the ordinary form, while the broccolies, the cabbages, and many other products of our kitchen gardens and fields owe the estimation in which they are held entirely to those peculiarities which, by an unhappy application of words, are called monstrous by botanists. Grafting, layering, the "striking" of cuttings, the formation of adventitious roots and buds, processes on which the cultivator so greatly relies for the propagation and extension of his plants, are also matters with which teratology concerns itself. Again the difficulty experienced occasionally in getting vines, strawberries, &c., to set properly, may sometimes be accounted for by that inherent tendency which some plants possess of exchanging an hermaphrodite for a unisexual condition. For reasons then of direct practical utility, no less than on purely scientific grounds, it is desirable to study these irregularities of growth, their nature, limits, and inducing causes; and to this end it is hoped the present work may, in some degree, contribute. FOOTNOTES: [1] An excellent summary of the history of Vegetable Teratology is given in Kirschleger's 'Essai historique de la Tératologie Végétale,' Strasburg, 1845. [2] In some instances diagrams and formulæ are given in explanation of the conformation of monstrous flowers; in general these require no further explanation than is given in the text, unless it be to state that the horizontal line--is intended to indicate the cohesion of the parts over which it is placed, while the vertical line | signifies the adhesion of the organs by whose side it is placed. The formula S S S S S ------------------------ | P P P P P | | ST ST ST ST ST shows that the sepals (S) are distinct, the petals (P) coherent, and the stamens (ST) adherent to the petals. [3] Wolff was the first to call attention to the great importance of the study of development. He was followed by Turpin, Mirbel, Schleiden, Payer, and others, and its value is now fully recognised by botanists. [4] Agardh, "Theoria Syst. Plant.," p. xxiii. [5] In the memoirs of Hopkirk, Kirschleger, Cramer, Hallier, and others, malformations are arranged primarily according to the organs affected, an arrangement which has only convenience to justify it. It is hoped that the index and the headings to the paragraphs in the present volume will suit the convenience of the reader as well as if the more artificial plan just alluded to had been adopted. [6] Cryptogamous plants are only incidentally alluded to in these pages, owing to their wide difference in structure from flowering plants. Attention may, also, here be called to a paper of M. de Seynes in a recent number of the Bulletin of the Botanical Society of France, vol. xiv, p. 290, tab. 5 et 6, in which numerous cases of malformation among agarics are recorded. See also same publication, vol. iv, p. 744; vol. v, p. 211; vol. vi, p. 496. [7] On this subject see a paper of M. Naudin in the 'Comptes Rendus,' 1867, t. 64, pp. 929-933. [8] It is probable that many terms and expressions calculated to mislead in the way above mentioned are made use of in the following pages. The inconsistency manifested by their use may be excused on the ground of ignorance of the true structure, and by the circumstance that in many cases facts alone are recorded without an explanation of them being offered. Moreover, it is desirable to act in conformity with the usual practice of botanical writers, and not to change established terminology, even if suspected to convey false ideas, until the true condition of affairs be thoroughly well ascertained by organogenetic research or other means. [9] A curious illustration of the latter class of alterations came under the writer's notice last summer (1868), and which he has reason to believe has not been previously recorded, viz. the persistence in an unwithered state of the petals at the base of the ripe fruit, in a strawberry. All the fruits on the particular plants alluded to were thus provided as it were with a white frill. Whether this be a constant occurrence in the particular variety is not known. VEGETABLE TERATOLOGY. BOOK I. DEVIATIONS FROM THE ORDINARY ARRANGEMENT OF ORGANS. As full details relating to the disposition or arrangement of the general organs of flowering plants are given in all the ordinary text-books, it is only necessary in this place to allude to the main facts at present known, and which serve as the standard of comparison with which all morphological changes are compared. Even in the case of the roots, which appear to be very irregular in their ramification, it has been found that, in the first instance at least, the rootlets or fibrils are arranged in regular order one over another, in a certain determinate number of vertical ranks, generally either in two or in four, sometimes in three or in five series. This regularity of arrangement (Rhizotaxy), first carefully studied by M. Clos, is connected with the disposition of the fibro-vascular bundles in the body of the root. This primitive regularity is soon lost as the plant grows. In the case of the leaves there are two principal modes of arrangement, dependent, as it would seem, on their simultaneous or on their successive development; thus, if two leaves on opposite sides of the stem are developed at the same time, we have the arrangement called opposite; if there are more than two, the disposition is then called verticillate or whorled. On the other hand, if the leaves are developed in succession, one after the other, they are found to emerge from the stem in a spiral direction. In either case the leaves are arranged in a certain regular manner, according to what are called the laws of Phyllotaxis, which need not be entered into fully here; but in order the better to estimate the teratological changes which take place, it may be well to allude to the following circumstances relating to the alternation of parts. The effect of this alternation is such, that no two adjacent leaves stand directly over or in front one of the other, but a little to one side or a little higher up. Now, in the alternate arrangement the successive leaves of each spiral cycle alternate one with another till the coil is completed. For the sake of clearness this may be illustrated thus:--Suppose the spiral cycle to comprise five leaves, numbered 1, 2, 3, 4, 5, then 2 would intervene between 1 and 3, and so on, while the sixth leaf would be the commencement of a new series, and would be placed exactly over 1. This arrangement may be thus formularised: 6 7 8 9 10 1 2 3 4 5 In the verticillate or simultaneous arrangement of leaves the case is somewhat different. Let us suppose a whorl of eight leaves, surmounted by a similar whorl of eight. In such a case it will generally be found that the whorls alternate one with another, as may be represented by this symbol: 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 The simplest illustration of this arrangement is seen in the case of decussate leaves, where those organs are placed in pairs, and the pairs cross one another at right angles. This may be expressed by the following symbol: 7 8 5 6 3 4 1 2 Thus, while in both the annular and the spiral modes of development the individual members of each complete series necessarily alternate one with another, in the former case the series themselves alternate, while in the successive arrangement they are placed directly one over the other. There are, of course, exceptions, but the rule is as has been stated, and the effect is to prevent one leaf from interfering with the development and growth of its neighbours. In the case of the whorled or simultaneous arrangement the conditions of growth must be uniform on all sides, but in the successive or spiral disposition the conditions influencing growth act with unequal force, on different sides of the stem, at the same time. In the whorl there is an illustration of radiating symmetry, while in the spiral arrangement there is a transition to the bilateral symmetry. There are frequent passages from one to the other even under normal circumstances; thus, while the one arrangement obtains in the ordinary leaves, the parts of the flower may be disposed according to the other method. In the annular disposition it generally happens that the rings are separated one from the other by the development of the stem between them, the internodes between the constituent leaves themselves of course being undeveloped; on the other hand, in the spiral or successive arrangement there is no such alternate growth and arrest of growth of the stem between the leaves, or between successive cycles, but the growth is, under favorable conditions, continuous--leaf is separated from leaf, and cycle from cycle, by the continually elongating stem. Thus, the two modes of growth correspond precisely with those observed in the case of definite and indefinite inflorescence respectively. [Illustration: FIG. 1.--Diagram showing the arrangement of parts in a complete, regular, pentamerous flower: _s_, sepals; _p_, petals; _st_, stamens; _o_, ovaries.] The same arrangements, that are observed in the disposition of the leaves, apply equally well to the several parts of the flower; thus, in what is for convenience considered the typical flower, there is a calyx of five or more distinct sepals, equal in size, and arranged in a whorl, a corolla of a similar number of petals alternating with the sepals, five stamens placed in the same position with reference to the petals, and five carpels alternating with the stamens. Throughout this book this arrangement is taken as the standard of reference. Nevertheless the spiral order does occur in the floral leaves as well as in those of the stem; it often happens, especially when the organs are numerous, that they form spiral series; and the same holds good very generally, when the parts of the flower are uneven in number, as in the very common quincuncial arrangement of the sepals, &c. To these general remarks, intended to show the agreement between the disposition of the leaves of the stem and those of the flower, it is merely necessary to add that the arrangement of the placentas, as well as that of the ovules borne on them, is also definite, and takes place according to methods explained in all the text-books, and on which, therefore, it is not necessary to dilate in this place. The branches of the stem or axis correspond for the most part in disposition with that of the leaves from the axils of which they originate, subject, however, to numerous disturbing causes, and to alterations from the usual or typical order brought about by the development of buds. These latter organs, as it seems, may be found in almost any situation, though their ordinary position is in the axil of a leaf or at the end of a stem or branch. The points just mentioned are of primary importance in structural botany, and as such are seized on not only by the morphologist, but by the systematic botanist, who finds in them the characters by which he may separate one group from another. Thanks to the labours of those observers who have devoted their attention to that difficult but most important branch of study, organogeny, or the investigation of the development of the various organs, and to the researches of the students of comparative anatomy or morphology, the main principles regulating the arrangement and form of the organs of flowering plants seem to be fairly well established, though in matters of detail much remains to be cleared up, even in such important points as the share which the axis takes in the construction of the flower and fruit, the nature of the placenta, the construction of the ovules, and other points. The facts already known justify the adoption of a standard or typical arrangement as just mentioned. The intrinsic value of this type is shown by the facility with which all varieties of form or arrangement may be explained by reference to certain modifications of it. It must, however, be considered as an abstraction, and should be looked on in the light rather of a scaffolding, which enables us to see the building and its several parts, than of the edifice itself, but which latter, from our imperfect knowledge and limited powers, we could not see without some such assistance. The typical form may be, hypothetically at least, considered as the primitive one transmitted by hereditary descent from generation to generation, and modified to suit the requirements of the individual, or in accordance with circumstances. If it be borne in mind that it is but an artificial contrivance, more or less true--a means to an end, and not the end itself--no harm will arise from its employment; and as knowledge increases, or as circumstances demand, the hypothetical type can be replaced by another more in accordance with the actual state of science. Teratological changes in the arrangement of organs depend upon arrest of growth, as when parts usually spirally arranged remain verticillate, owing to the non-development of the internodes, or to excessive growth, or development; but in many instances it is impossible, without studying the development of the malformed flower, to ascertain whether the altered arrangement is due to an excessive or to a diminished action. Practically, however, it is of comparatively little importance to know whether, say, the isolation of parts, that are usually combined together, is congenital (_i.e._ the result of an arrest of growth preventing their union), or whether it be due to a separation of parts primitively undivided; the effect remains the same, though the cause may have been very different. The principal alterations to be mentioned under this head may therefore be conveniently arranged under the following categories:--Union, Independence, Displacement, Prolification, Heterotaxy, and Heterogamy. PART I. UNION OF ORGANS. The union of parts, usually separate in their adult condition, is of very common occurrence as a malformation. The instances of its manifestation admit of being grouped under the heads of Cohesion, where parts of the same whorl, or of the same organ, are united together; and of Adhesion, where the union takes place between members of different whorls, or between two or more ordinarily wholly detached and distinct parts. In either case, the apparent union may be congenital (that is, the result of a primitive integrity or a lack of separation), or it may really consist in a coalition of parts originally distinct and separate. In practice it is not always easy to distinguish between these two different conditions. Indeed, in most cases it cannot be done without tracing the development of the flower throughout all its stages. It is needless to make more than a passing allusion to the frequency with which both congenital integrity or subsequent coalescence of organs exist under ordinary circumstances. Considered as a teratological phenomenon, union admits of being grouped into several subdivisions, such as Cohesion, Adhesion, Synanthy, Syncarpy, Synophty, &c. Each of these subdivisions will be separately treated, but it maybe here said that, in all or any case, the degree of fusion may be very slight, or it may be so perfect that there may be a complete amalgamation of two or more parts, while to all outward appearance the organ may be single. The column of Orchids may be referred to as an illustration under natural circumstances of the complete union of many usually distinct parts. In the uncertainty that exists in many cases as to the real nature of the occurrence, it would be idle to attempt to explain the causes of fusions. It is clear, however, that an arrest of development will tend towards the maintenance of primordial integrity (congenital fusion), and that pressure will induce the coalition of organs primarily distinct. CHAPTER I. COHESION. Following Augustin Pyranius De Candolle, botanists have applied the term cohesion to the coalescence of parts of the same organ or of members of the same whorl; for instance, to the union of the sepals in a gamosepalous calyx, or of the petals in a gamopetalous corolla. It may arise either from a union between organs originally distinct, or more frequently from a want of separation between parts, which under general circumstances become divided during their development. Nothing is more common as a normal occurrence, while viewed as a teratological phenomenon it is also very frequent. For the purposes of convenience it admits of subdivision into those cases wherein the union takes place between the branches of the same plant, or between the margins of the same leaf-organ, or between those of different members of the same whorl. =Cohesion between the axes of the same plant.=--This cohesion may occur in various manners. Firstly. The branches of the main stem may become united one to the other. Secondly. Two or more stems become joined together. Thirdly. The branches become united to the stem; or, lastly, the roots may become fused one with another. [Illustration: FIG. 2--Cohesion of two branches in _Dipsacus sylvestris_.] The first of these is most commonly met with, doubtless owing to the number of the branches and the facilities for their union. An illustration of it is afforded by the figure (fig. 2), showing cohesion affecting the branches of a teazle (_Dipsacus sylvestris_). Union of the branches may be the result of an original cohesion of the buds, while in other cases the fusion does not take place until after development has proceeded to some extent. Of this latter kind illustrations are common where the branches are in close approximation; if the bark be removed by friction the two surfaces are very likely to become united (natural grafting). Such a union of the branches is very common in the ivy, the elder, the beech, and other plants. It may take place in various directions, lengthwise, obliquely, or transversely, according to circumstances. This mode of union belongs, perhaps, rather to the domain of pathology than of teratology. Some of the instances that have been recorded of very large trees, such as the chestnut of Mount Ætna, are really cases where fusion has taken place between several of the branches, or suckers, thrown out from the same original stem.[10] The same process of grafting occurs sometimes in the roots, as in _Taxus baccata_ mentioned by Moquin, and also in the aerial roots of many of the tropical climbing plants, such as _Clusia rosea_, &c. [Illustration: FIG. 3.--Fasciation in Lettuce.] =Fasciation.=--In the preceding instances of union between the branches, &c., the actual number of the fused parts is not increased; but if it happen that an unusual number of buds be formed in close apposition, so that they are liable to be compressed during their growth, union is very likely to take place, the more so from the softness of the young tissues. In this way it is probable that what is termed fasciation is brought about. This is one of the most common of all malformations, and seems to affect certain plants more frequently than others. In its simplest form it consists of a flat, ribbon-like expansion of the stem or branch; cylindrical below, the branches gradually lose their pristine form, and assume the flattened condition. [Illustration: FIG. 4.--Fasciation in _Asparagus_.] [Illustration: FIG. 5.--Fasciated branch of _Pinus Pinaster_.] Very generally the surface is striated by the prominence of the woody fibres which, running parallel for a time, converge or diverge at the summit according to the shape of the branch. If the rate of growth be equal, or nearly so, on both sides, the stem retains its straight direction, but it more generally happens that the growth on one side is more rapid and more vigorous than on the other, and hence arises that curvature of the fasciated branch so commonly met with, _e.g._ in the ash (_Fraxinus_), wherein it has been likened to a shepherd's crook. It is probable that almost any plant may present this change. It occurs alike in herbaceous and in woody plants, originating in the latter case while the branches are still soft. It may be remarked that, in the case of herbaceous plants, the fasciation always affects the principal stem, while, on the other hand, in the case of trees and shrubs the deformity occurs most frequently in the branches; thus, while in the former it may be said that the whole of the stem is more or less affected, in the latter it is rare to see more than one or two branches of the same tree thus deformed. It is a common thing for the fasciated branch to divide at the summit into a number of subdivisions. These latter may be deformed like the parent branch, or they may resume the ordinary aspect of the twigs. [Illustration: FIG. 6.--Fasciation and spiral torsion in the stem of _Asparagus_.] Sometimes the flattened stem is destitute of buds, at other times, these organs are scattered irregularly over its surface or are crowded together in a sort of crest along the apex. When, as often happens, the deformity is accompanied with a twisting of the branch spirally, the buds may be placed irregularly, or in other cases along the free edge of the spiral curve. In a specimen of _Bupleurum falcatum_ mentioned by Moquin the spiral arrangement of the leaves was replaced by a series of perfect whorls, each consisting of five, six, seven, or eight segments, and there was a flower-stalk in the axil of each leaf. When flowers are borne on these fasciated stems they are generally altered in structure; sometimes the thalamus itself becomes more or less fasciated or flattened, and the different organs of the flower are arranged on an elliptical axis. A case of this nature is described by Schlechtendal ('Bot. Zeit.,' 1857, p. 880), in _Cytisus nigricans_, and M. Moquin-Tandon describes an instance in the vine in one flower of which sepals, petals, stamens, and ovary were abortive, while the receptacle was hypertrophied and fasciated, and bore on its surface a few adventitious buds.[11] The pedicels of _Streptocarpus Rexii_ have also been observed in a fasciated state.[12] It has been occasionally observed that the fasciated condition is hereditary; thus, Moquin relates that some seeds of a fasciated _Cirsium_ reproduced the same condition in the seedlings,[13] while a similar tendency is inherited in the case of the cockscomb (_Celosia_). With reference to the nature of the deformity in question there is a difference of opinion; while most authors consider it to be due to the causes before mentioned, Moquin was of opinion that fasciation was due to a flattening of a single stem or branch. Linnæus, on the other hand, considered such stems to be the result of the formation of an unusual number of buds, the shoots resulting from which became coherent as growth proceeded:--"_Fasciata dici solet planta cum plures caules connascuntur, ut unus ex plurimis instar fasciæ evadat et compressus_" (Linn., 'Phil. Bot.,' 274). A similar opinion was held by J. D. Major in a singular book entitled 'De Plantâ, Monstrosa, Gottorpiensi,' Schleswig, 1665, wherein the stem of a _Chrysanthemum_ is depicted in the fasciated condition. [Illustration: FIG. 7.--Fasciation in the scape of the Dandelion (_Leontodon Taraxacum_).] The striæ, which these stems almost invariably present, exhibit the lines of junction, and the spiral or other curvatures and contraction, which are so often met with, may be accounted for by the unequal growth of one portion of the stem as contrasted with that of another. Against this view Moquin cites the instances of one-stemmed plants, such as _Androsace maxima_, but, on the other hand, those herbaceous plants having usually but a single stem not unfrequently produce several which may remain distinct, but not uncommonly become united together. Prof. Hincks[14] cites cases of this kind in _Primula vulgaris_, _Hieracium aureum_, and _Ranunculus bulbosus_. I have myself met with several cases of the kind in _Primula veris_, in the Polyanthus, in the Daisy, and in the _Leontodon Taraxacum_, in which latter a fusion of two or more flower-stems bearing at the top a composite flower, and made up of two, three, four, or more flowers combined together, and containing all the organs that would be present in the same flowers if separate, is very common. Moquin's second objection is founded upon the fact that, in certain fasciated stems, the branches are not increased in number or altered in arrangement from what is usual; but however true this may be in particular cases, it is quite certain that in the majority of instances a large increase in the number of leaves and buds is a prominent characteristic of fasciated stems. Another argument used by the distinguished French botanist to show that fasciated stems are not due to cohesion of two or more stems, is founded on the fact that a transverse section of a fasciated stem generally shows an elliptical outline with but a single central canal. On the other hand, if two branches become united and a transverse section be made, the form of the cut surface would be more or less like that of the figure 8[Symbol: 8 turned 90°], although in old stems this may give place to an elliptical outline, but even then traces of two medullary canals may be found. This argument is very deceptive, for the appearance of the transverse section must depend, not only on the intimacy of their union, but also on the internal structure of the stems themselves. When two flowers cohere without much pressure they exhibit uniting circles somewhat resembling the figure of 8[Symbol: 8 turned 90°], but when more completely combined they have an outline of a very elongated figure, and something similar is to be expected in herbaceous stems. Even the elongated pith of a transversely cut, woody, fasciated stem only marks the intimate union of several branches, and Prof. Hincks, whose views the writer entirely shares, has noticed instances of the union of two, and of only two, stems where the internal appearance was the same as in other fasciations. Moquin, moreover, raises the objection that it is unlikely that several branches should become united lengthwise in one plane only, and, further, that in the greater number of fasciations all the other branches which should be present are to be found--not one is wanting, not one has disappeared, as might have been anticipated had fusion taken place. In raising this objection, Moquin seems not sufficiently to have considered the circumstance that the buds in these cases are in one plane from the first, and are all about equal in point of age and size. The last objection that Moquin raises to the opinion that fasciation is the result of a grafting process is, that in such a case, examples should be found wherein the branches are incompletely fused, and where on a transverse section traces of the medullary canals belonging to each branch should be visible. The arrangement of leaves or buds on the surface should also in such a case indicate a fusion of several spiral cycles or whorls. To this it may be replied that such cases are met with very frequently indeed. A figure is given by De Candolle[15] of a stem of _Spartium junceum_ having several branches only imperfectly fasciated. Fasciated stems, then, seem to be best explained, as is stated by Prof. Hincks, "on the principle of adhesion arising in cases where from superabundant nourishment, especially if accompanied by some check or injury, numerous buds have been produced in close proximity, and the supposition that these growths are produced by the dilatation of a single stem is founded on a false analogy between fasciated stems and certain other anomalous growths." It will not, of course, be forgotten that this fasciated condition occurs so frequently in some plants as almost to constitute their natural state, _e.g._ _Sedum cristatum_, _Celosia_, &c. This condition may be induced by the art of the gardener--"_Fit idem arte, si plures caules enascentes cogantur penetrare coarctatum spatium et parturiri tanquam ex angusto utero, sic sæpe in Ranunculo, Beta, Asparago, Hesperide Pinu, Celosiâ, Tragopogone, Scorzonerâ Cotula foetida_," Linnæus op. cit. Plot, in his 'History of Oxfordshire,' considers fasciation to arise from the ascent of too much nourishment for one stalk and not enough for two, "which accident of plants," says Plot, the German virtuosi ('Misc. Curios. Med. Physic. Acad. Nat. Cur.,' Ann. i, Observ. 102,) "think only to happen after hard and late winters, by reason whereof, indeed, the sap, being restrained somewhat longer than ordinary, upon sudden thaws may probably be sent up more forcibly, and so produce these fasciated stalks, whereas the natural and graduated ascent would have produced them but single." Prof. Hincks' explanation is, however, more near to the truth, and his opinion is borne out by the frequency with which this change is met with in certain plants which are frequently forced on during their growth, as lettuce, asparagus, endive, &c., all of which are very subject to this change. In the 'Transactions of the Horticultural Society of London,' vol. iv, p. 321, Mr. Knight gives an account of the cultivation of the cockscomb, so as to ensure the production of the very large flower-stalks for which this plant is admired. The principal points in the culture were the application of a large quantity of stimulating manure and the maintenance of a high temperature. One of them so grown measured eighteen inches in width. The list which is appended is intended to show those plants in which fasciation has been most frequently observed. It makes no pretension to be complete, but is sufficiently so for the purpose indicated: the * denotes the especial frequency of the change in question; the ! indicates that the writer has himself seen the plant, so marked, affected in this way. The remainder have been copied from various sources. EXOGENS. [Greek: alpha]. _Herbaceous._ Ranunculus tripartitus. * bulbosus! Philonotis. Delphinium elatum. * sp.! Hesperis matronalis. *Cheiranthus Cheiri! *Matthiola incana! *Brassica oleracea! var. pl. inflor. Linum usitatissimum! Althæa rosea! Lavatera trimestris. Geranii sp. Tropæolum majus! Viola odorata inflor.! Reseda odorata! Fragaria vesca. Ervum lens. Trifolium resupinatum. repens! pratense! Saxifraga mutata. irrigua. Bupleurum falcatum. Bunium flexuosum. *Sedum reflexum! cristatum! Epilobium augustifolium! Momordica Elaterium! Gaura biennis. Cotula foetida. Barkhausia taraxacifolia. Carlina vulgaris! Apargia autumnalis. *Leontodon Taraxacum inflor.! Centaurea Scabiosa. *Cichorium Intybus! Hieracium Pilosella. aureum. umbellatum. *Chrysanthemum Leucanthemum. indicum! Anthemis nobilis. arvensis. Cirsium lanceolatum. Conyza squarrosa! Inula dysenterica! Tragopogon porrifolium. Cnicus palustris. Carduus arvensis! Helianthus tuberosus! annuus. Cineraria palustris. Helianthus sp.! Dahlia variabilis. Bellis perennis inflor.! Coreopsis sp.! Crepis virens. Lactuca sativa! Zinnia elegans. *Campanula medium! rapunculoides. thyrsoidea. Dipsacus pilosus. fullonum. silvestris. Knautia arvensis. Phyteuma orbiculare. Jasione montana. *Linaria purpurea! Antirrhinum majus! Veronica amethystea. Veronica maritima. sp. Russellia juncea! Digitalis purpurea! Ajuga pyramidalis. Hyssopus officinalis. Dracocephalum moldavicum. Myosotis scorpioides. Echium pyrenaicum. simplex. Stapeliæ sp. Lysimachia vulgaris! Androsace maxima. Primula veris inflor.! denticulata inflor.! Polemonium coeruleum. Convolvulus sepium! arvensis! Plantago media. *Euphorbia Characias. exigua. * Cyparissias. Suæda maritima. *Celosia sp. Beta vulgaris inflor.! Phytolacca sp. [Greek: beta]. _Woody._ Berberis vulgaris. Hibiscus syriacus! Acer pseudo-platanus! Dodonæa viscosa. Sterculia platanifolia. Euonymus japonicus! Vitis vinifera inflor.! Spartium Scoparium! Spartium junceum! Cytisus Laburnum. nigricans. Chorozema ilicifolium. Amorpha sp. Phaseolus sp. Prunus sylvestris. Laurocerasus! Rosa sp.! Spiræa sp.! Cotoneaster microphylla! Ailanthus glandulosus. *Fraxinus Ornus! * excelsior! Melia Azedarach. Xanthoxylum sp.! Sambucus nigra.! Aucuba japonica. Erica sp. cult. Jasminum nudiflorum! officinale! Olea europoea. Punica Granatum. Ilex aquifolium! Daphne indica. Daphne odora. Suæda fruticosa. Ulmus campestris. Alnus incana. Salix vitellina, &c.! Thuja orientalis. Pinus pinaster! sylvestris! Abies excelsa! Taxus baccata. Larix europoea. ENDOGENS. Lilium Martagon. candidum! *Fritillaria imperialis! Asparagus officinalis! Hyacinthus orientalis! Tamus communis! Narcissi sp.! Gladiolus sp. Zea Mays. Filices. See also--Moquin-Tandon, 'Elem. Ter. Veget.,' p. 146; C. O. Weber, 'Verhandl. Nat. Hist.,' Vereins, f. d. Preuss., Rheinl. und Westphal., 1860, p. 347, tab. vii; Hallier, 'Phytopathol.,' p. 128; Boehmer, 'De plantis Fasciatis,' Wittenb., 1752. =Cohesion of foliar organs.=--This takes place in several ways, and in very various degrees; the simplest case is that characterised by the cohesion of the margins of the same organ, as in the condition called perfoliate in descriptive works, and which is due either to a cohesion of the margins of the basal lobes of the leaf, or to the development of the leaf in a sheathing or tubular manner. As an abnormal occurrence, I have met with this perfoliation in a leaf of _Goodenia ovata_. The condition in question is often loosely confounded with connation, or the union of two leaves by their bases. In other cases the union takes place between the margins of two or more leaves. =Cohesion of margins of single organs.=--The leaves of Hazels may often be found with their margins coherent at the base, so as to become peltate, while in other cases, the disc of the leaf is so depressed that a true pitcher is formed. This happens also in the Lime _Tilia_, in which genus pitcher- or hood-like leaves (_folia cucullata_) may frequently be met with. There are trees with leaves of this character in the cemetery of a Cistercian Monastery at Sedlitz, on which it is said that certain monks were once hung: hence the legend has arisen, that the peculiar form of the leaf was given in order to perpetuate the memory of the martyred monks. ('Bayer. Monogr. _Tiliæ_,' Berlin, 1861.) It is also stated that this condition is not perpetuated by grafting. [Illustration: FIG. 8.--Pitcher-shaped leaf of _Pelargonium_.] I have in my possession a leaf of _Antirrhinum majus_, and also a specimen of _Pelargonium_, wherein the blade of the leaf is funnel-like, and the petiole is cylindrical, not compressed, and grooved on the upper surface, as is usually the case. A comparison of the leaves of _Pelargonium peltatum_ with those of _P. cucullatum_ ('Cav. Diss.,' tab., 106) will show how easy the passage is from a peltate to a tubular leaf. In these cases the tubular form may rather be due to dilatation than to cohesion. M. Kickx[16] mentions an instance of the kind in the leaves of a species of _Nicotiana_, and also figures the leaf of a rose in which two opposite leaflets presented themselves in the form of stalked cups. Schlechtendal[17] notices something of the same kind in the leaf of _Amorpha fruticosa_; Treviranus[18] in that of _Aristolochia Sipho_. M. Puel[19] describes a leaf of _Polygonatum multiflorum_, the margins of which were so completely united together, as only to leave a circular aperture at the top, through which passed the ends of the leaves. The Rev. Mr. Hincks, at the meeting of the British Association at Newcastle (1838), showed a leaf of a Tulip, whose margins were so united that the whole leaf served as a hood, and was carried upwards by the growing flower like the calyptra of a Moss. The margins of the stipules are also occasionally united, so as to form a little horn-shaped tube. I have met with instances of this kind in the common white clover, _Trifolium repens_, where on each side of the base of the petiole the stipules had the form just indicated. That the bracts also may assume this condition, may be inferred from the peculiar horn-like structures of _Marcgraavia_, which appear to originate from the union of the margins of the reflected leaf. =Tubular petals= occur normally in some flowers, as _Helleborus_, _Epimedium_, _Viola_, &c., and as an exceptional occurrence I have seen them in _Ranunculus repens_, while in _Eranthis hyemalis_ transitions may frequently be seen between the flat outer segments of the perianth and the tubular petals. To Dr. Sankey, of Sandywell Park, I am indebted for the flower of a Pelargonium, in which one of the petals had the form of a cup supported on a long stalk. This cup-shaped organ was placed at the back of the flower, and had the dark colour proper to the petals in that situation. I have seen a petal of Clarkia similarly tubular, while some of the cultivated varieties of _Primula sinensis_ exhibit tubular petals so perfect in shape as closely to resemble perfect corollas. [Illustration: FIG. 9.--_Eranthis hyemalis_. Transition from flat sepal to tubular petal.] Like the petals, the stamens, and even the styles, assume a hollow tubular form. This change of form in the case of the stamens is, of course, usually attended by the petaloid expansion of the filament, or anther, and the more or less complete obliteration of the pollen sacs, as in Fuchsias, and in some double-flowered Antirrhinums.[20] So also in some semi-double varieties of _Narcissus poeticus_, and in _Aquilegia_. By the late Professor Charles Morren, this affection of the stamens and pistils was called _Solenaidie_,[21] but as a similar condition exists in other organs, it hardly seems worth while to adopt a special term for the phenomenon, as it presents itself in one set of organs. In many of these cases it is difficult to say whether the cup-like or tubular form is due to a dilatation or hollowing out of the organ affected, or to a fusion of its edges. The arrangement of the veins will in some cases supply the clue, and in others the regularity of form will indicate the nature of the malformation, for in those instances where the cup is the result of expansion, its margin is more likely to be regular and even than in those where the hollow form is the result of fusion. =Cohesion of several organs by their margins:--leaves, &c.=--The union of the margins of two or more different organs is of more common occurrence than the preceding, the leaves being frequently subjected to this change. Occasionally, the leaflets of a compound leaf have been observed united by their margins, as in the strawberry, the white trefoil, and others. Sometimes the union takes place by means of the stalks only. I have an instance of this in a Pelargonium, in _Tropæolum majus_, and _Strelitzia regina_; in other cases, the whole extent of the leaf becomes joined to its neighbour, the leaves thus becoming completely united by their edges, as in those of _Justicia_, _oxyphylla_.[22] M. Clos[23] has observed the same thing in the leaves of the lentil _Ervum lens_, conjoined with fasciation of the stem, and many other examples might be given. Some of the recorded cases are probably really due to fission of one leaf into two rather than to fusion. Although usually the lower portions of the leaf are united together, leaving the upper parts more or less detached, there are some instances in which the margins of the leaf at their upper portion have been noticed to be coherent, while their lower portions, with their stalks, were completely free.[24] Cohesion of the leaves frequently accompanies the union of the branches and fasciation as might have been anticipated. Moquin cites the fenestrated leaves of _Dracontium pertusum_, as well as some cases of a similar kind that are occasionally met with, as instances of the cohesion of the margins at the base and apex of the leaf, which thus appears perforated. This appearance, however, is probably due to some other cause. When the leaves are verticillate and numerous, and they become coherent by their margins, they form a foliaceous tube around the stem. When there are but two opposite leaves, and these become united by their margins, we have a state of things precisely resembling that to which the term connate is applied. Fusion of the edges of the cotyledons also occasionally takes place, as in _Ebenus cretica_.[25] It has also been observed in _Tithonia_, and is of constant occurrence in the seed leaves of some _Mesembryanthema_. This condition must be carefully distinguished from the very similar appearance produced by quite a different cause, viz., the splitting of one cotyledon into two, which gives rise to the appearance as if two were partially united together. Some of the ascidia or pitcher-like formations are due to the cohesion of the margins of two leaves, as in a specimen of _Crassula arborescens_, observed by C. Morren. [Illustration: FIG. 10.--Two-leaved pitcher of _Crassula arborescens_, after C. Morren.] The stipules may also be fused together in different ways; their edges sometimes cohere between the leaf and the stem, and thus form a solitary intra-axillary stipule. At other times they become united in such a manner as to produce a single notched stipule opposite to the leaf. Again, in other cases, they are so united on each side of the stem, that in place of four there seem only to exist two, common to the two leaves as in the Hop. To the Rev. M. J. Berkeley I am indebted for specimens of a curious pitcher-like formation in the garden Pea. The structure in question consisted of a stalked foliaceous cup proceeding from the inflorescence. On examination of the ordinary inflorescence, there will be seen at the base of the upper of two flowers a small rudimentary bract, having a swollen circular or ring-like base, from which proceeds a small awl-shaped process, representing the midrib of an abortive leaf. In some of Mr. Berkeley's specimens, the stipules were developed as leafy appendages at the base of the leaf-stalk or midrib, the latter retaining its shortened form, while, in others, the two stipules had become connate into a cup, and all trace of the midrib was lost. The cup in question would thus seem to have been formed from the connation of two stipules which are ordinarily abortive. Cohesion of the bracts by their edges, so as to form a tubular involucre, or by their surfaces, so as to form a cupule, is not of uncommon occurrence, under natural conditions, and may be met with in plants which ordinarily do not exhibit this appearance. =Cohesion of the sepals= in a normally polypetalous calyx renders the latter gamosepalous, and is not of uncommon occurrence, to a partial extent, though rarely met with complete. I have observed a junction of the sepals to be one of the commonest malformations among Orchids, indeed such a state of things occurs normally in _Masdevallia Cypripedium_, &c. An illustration of this occurrence is given by Mr. J. T. Moggridge in _Ophrys insectifera_, in 'Seemann's Journal of Botany,' 1866, p. 168, tab. 47. In Orchids, this cohesion of sepals is very often co-existent with other more important changes, such as absence of the labellum, dislocation of the parts of the flower, &c. [Illustration: FIG. 11.--Gamopetalous flower of _Papaver bracteatum_.] =Cohesion of the petals.=--Linnæus mentions the occurrence of cohesion of the petals in _Saponaria.[26]_ Moquin notices a Rose in which the petals were united into a long tube, their upper portions were free and bent downwards, forming a sort of irregular limb. An instance of the polypetalous regular perianth of _Clematis viticella_ being changed into a monopetalous irregular one, like the corolla of Labiates, is recorded by Jaeger.[27] There is in cultivation a variety of _Papaver bracteatum_, in which the petals are united by their margins so as to form a large cup. Under normal circumstances, the petals become fused together by their edges along their whole extent, at the base only, at the apex only, as in the Vine, or at the base and apex, leaving the central portions detached. Indications of the junction of the petals may generally be traced by the arrangement of the veins, or by the notches or lobes left by imperfect union. In Crocuses I have frequently met with cohesion of the segments of the perianth, by means of their surfaces, but the union was confined to the centre of the segment, leaving the rest of the surfaces free. =Cohesion of the stamens.=--Under natural circumstances, cohesion of the stamens is said to take place either by the union of their filaments, so as to form one, two, or more parcels (Monadelphia, Diadelphia, Polyadelphia); at other times, by the cohesion of the anthers (Syngenesia), in which latter case the union is generally very slight. It must be remembered, however, that the so-called cohesion of the filaments is in many cases due rather to the formation of compound stamens, _i.e._ to the formation from one original staminal tubercle of numerous secondary ones, so that the process is rather one of over development than of fusion or of disjunction. These conditions may be met with as accidental occurrences in plants or in flowers, not usually showing this arrangement. Thus, for instance, Professor Andersson, of Stockholm, describes a monstrosity of _Salix calyculata_, in which the stamens were so united together as to form a tube open at the top like a follicle.[28] This is an exaggerated degree of that fusion which exists normally in _Salix monandra_, in Cucurbits and other plants. =Cohesion of the pistils= is also of very frequent occurrence in plants, under ordinary circumstances, but is less commonly met with than might have been expected as a teratological phenomenon. Further details relating to cohesion of the various parts of the flower are cited in Moquin-Tandon, 'El. Ter. Veg.,' p. 248; 'Weber. Verhandl. Nat. Hist. Vereins f. d. Preuss. Rheinl. und Westphal.,' 1860, p. 332, tabs. 6 et 7. =Formation of ascidia or pitchers.=--In the preceding paragraphs, the formation of tubular or horn-like structures, from the union of the margins of one organ, or from the coalescence, or it may be from the want of separation of various organs, has been alluded to, so that it seems only necessary now, by way of summary, to mention the classification of ascidia proposed by Professor Charles Morren[29], who divides the structures in question into two heads, according as they are formed from one or more leaves. The following list is arranged according to the views of the Belgian savant, and comprises a few additional illustrations. Those to which the ! is affixed have been seen by the writer himself; the * indicates the more frequent occurrence of the phenomenon in some than in other plants. Those plants, such as _Nepenthes_, &c., which occur normally and constantly, are not here included. Possibly some of the cases would be more properly classed under dilatation or excavation. ASCIDIA. A. _Monophyllous_. 1. Sarracenia-like pitchers, formed by a single leaf, the edges of which are united for the greater portion of their length, but are disunited near the top, so as to leave an oblique aperture. *Brassica oleracea (several of the cultivated varieties)! *Tilia europæa! Pelargonium inquinans! Staphylea pinnata. Amorpha fruticosa. Pisum sativum! Lathyrus tuberosus. Vicia sp. Gleditschia sp. Ceratonia siliqua. Trifolium repens! Cassia marylandica. Mimosa Lophantha. Rosa centifolia. gallica. Begonia sp. Bellis perennis! Nicotiana sp. Goodenia ovata! Antirrhinum majus! Vinca rosea. Polygonum orientale. Aristolochia sipho? Codiæum variegatum var.! Spinacia oleracea. Corylus avellana! Polygonatum multiflorum. Xanthosoma appendiculatum! 2. Calyptriform or hood-like pitchers, formed by the complete union of the margins, and falling off by a transverse fissure (as in the calyx of Escholtzia). Tulipa Gesneriana. B. _Polyphyllous._ 1. Diphyllous, formed by the union of two leaves into a single cup, tube, or funnel, &c. Pisum sativum (stipules)! Crassula arborescens. Polygonatum multiflorum. 2. Triphyllous, formed by the union of three leaves. Paris quadrifolia var. Besides the above varieties of ascidia formed from the union of one or more leaves, there are others which seem to be the result of a peculiar excrescence or hypertrophy of the leaf. Such are some of the curious pitcher-like structures met with occasionally in the leaves of cabbages, lettuces, Aristolochia, &c. See Hypertrophy, cup-like deformities, &c. In addition to other publications previously mentioned, reference may be made to the following treatises on the subject of ascidia:--Bonnet, 'Rech. Us. Feuilles,' p. 216, tab. xxvi, f. 1, _Brassica_; De Candolle, 'Trans. Hort. Soc.,' t. v, pl. 1, _Brassica_; Id., 'Org. Veget.,' I, 316; 'Bull. Soc. Bot. Fr.,' I, p. 62, _Polygonatum_; 'Bull. Acad. Belg.,' 1851, p. 591, _Rosa_; Hoffmann, 'Tijdschrift v. Natuur. Geschied.,' vol. viii, p. 318, tab. 9, _Ceratonia_; C. Mulder, 'Tijdschrift, &c.,' vol. vi, p. 106, tab. 5, 6, _Trifolium_, _Mimosa_, _Staphylea_;' Molkenboer,' p. 115, t. 4, _Brassica_. FOOTNOTES: [10] See a curious instance of this kind in the branches of _Pinus_. 'Regel. Garten Flora,' vol. 8, tab. 268. [11] 'Bull. Soc. Bot. France,' 1860, p. 881. [12] Ibid., 1861, p. 708. [13] Ibid., 1860, p. 923. [14] 'Proc. Linn. Soc.,' April 5, 1853. [15] 'Organ. Végét.,' pl. iii, fig. 1. [16] 'Bull. Acad. Roy. Bruxelles,' t. xviii, p. i and p. 591. [17] 'Linnæa,' tom. 13, p. 383. [18] 'Verhandl. Nat. Hist. Vereins,' 1859, Bonn, tom. xvi, tab. 3. [19] 'Bull. Soc. Bot. Fr.,' vol. i, p. 62. [20] 'Report of Internat. Bot. Congress,' London, 1866, p. 131, tab. vii, figs. 10-13. [21] 'Bull. Acad. Roy. Belg.,' t. xviii, 2nd part, p. 179. [22] D. C., 'Organ. Végét.,' pl. xvii, fig. 3, and pl. xlviii, fig. 2. [23] 'Mém. Acad. Toulouse,' 1862. [24] Bonnet, 'Recherches Us. feuill.,' pl. xxi, fig. 2. [25] De Candolle, 'Mém. Lég.,' pl. v, fig. 14. [26] 'Phil. Bot.,' § 125. [27] 'Nov. Act. Acad. Nat. Cur.,' 14, p. 642, t. xxxvii. [28] 'Journal of the Linn. Soc. Bot.,' vol. iv, p. 55. [29] 'Bull. Acad. Roy. Bruxelles,' 1838, t. v, p. 582. 'Bull. Acad. Roy. Belg.,' 1852, t. xix, part iii, p. 437. CHAPTER II. ADHESION. Adhesion, so called, occurs either from actual union of originally distinct members of different whorls or from the non-occurrence of that separation which usually takes place between them. It is thus in some degree a graver deviation than cohesion, and is generally a consequence of, or at least is coexistent with, more serious changes; thus if two leaves of the same whorl are coherent the change is not very great, but if two leaves belonging to different whorls, or two leaves in the same spiral cycle are adherent, a deformation in the axis or a certain amount of dislocation must almost necessarily exist. Adhesion as a normal occurrence is usually the result of a lack of separation rather than of union of parts primitively separate. Instances of adhesion between different organs is seen under ordinary circumstances in the bract of the Lime tree, which adheres to the peduncle, also in _Neuropeltis_, while in _Erythrochiton hypophyllanthus_ the cymose peduncles are adherent to the under surface of the leaf. Adhesion between the axes of the same plant is sufficiently treated of under the head of Cohesion, from which it is in this instance impossible to make a distinction. Adhesion of the inflorescence is necessarily a frequent accompaniment of fasciation and cohesion of the branches. =Adhesion of foliar organs= may occur either between the margins or between the surfaces of the affected parts; in the former case there is almost necessarily more or less displacement and change of direction, such as a twisting of the stem and a vertical rather than a horizontal attachment of the foliar organ to it; hence it generally forms but a part of other and more important deviations. =Adhesion of leaves by their surfaces.=--The union of leaves by their surfaces is not of very frequent occurrence, many of the instances cited being truly referable to other conditions. Bonnet describes the union of two lettuce leaves, and Turpin that of two leaves of _Agave americana_, in which latter the upper surface of one leaf was adherent to the lower surface of the leaf next above it, and I have myself met with similar instances in the wallflower and in lettuce and cabbage leaves; other instances have been mentioned in _Saxifraga_, _Gesnera_, _&c._[30] In these cases, owing to the non-development of the internodes, the nascent leaves are closely packed, and the conditions for adhesion are favorable, but in most of the so-called cases of adhesion of leaf to leaf by the surface, a preferable explanation is afforded either by an exuberant development (hypertrophy) or by chorisis (see sections on those subjects). Thus, when a leaf of this kind is apparently so united, that the lower surface of one is adherent to the corresponding surface of another, the phenomenon is probably due rather to extra development or to fission. There is an exception to this, however, in the case of two vertically-erect leaves on opposite sides of the stem; here the two upper or inner surfaces may become adherent, as in an orange, where two leaves were thus united, the terminal bud between them being suppressed or abortive. Adhesion between the membranous bract of _Narcissus poeticus_ and the upper surface of the leaf is described by Moquin.[31] The same author mentions having seen a remarkable example of adhesion in the involucels of _Caucalis leptophylla_, the bracts of which were soldered to the outer surface of the flowers. M. Bureau[32] mentions an instance wherein the spathe of _Narcissus biflorus_ was partially twisted in such a manner that the lower surface of its median nerve was adherent to the corresponding surface of one of the sepals, mid-rib to mid-rib, thus apparently confirming a law of G. de Hilaire, that when two parts of the same individual unite, they generally do so by the corresponding surfaces or edges, but the rule is probably not so general in its application as has been supposed. =Adhesion of foliar to axile organs.=--The appendicular organs may likewise be found united to the axile ones. This union takes place in many ways; sometimes the leaves do not become detached from the stem for a considerable distance, as in the so-called decurrent leaves, at other times the leaves are prolonged at their base into lobes, which are directed along the stem, and are united with it. Turpin records a tendril of a vine which was fused with the stem for some distance, and bore leaves and other tendrils. Union of the leaf or bract with the flower-stalk is not uncommon. It occurs normally in the Lime and other plants. =Adhesion of the sepals to the petals= is spoken of by Morren as calyphyomy, [Greek: kalyx phyomai.][33] Moquin cites an instance in _Geranium nodosum_, in which one petal was united by its lower surface to one of the segments of the calyx. A similar circumstance has been observed in _Petunia violacea_ by Morren. Duchartre describes an instance wherein one of the outer sepals of _Cattleya Forbesii_ was adherent to the labellum.[34] =Adhesion of the stamens to the petals= is of common occurrence under natural circumstances. Cassini has described a malformation of _Centaurea collina_, in which two of the five stamens were completely grafted with the corolla, the three others remaining perfectly free. Adhesion of the petals to the column is not of infrequent occurrence among Orchids. I have observed cases of the adhesion of the segments of the perianth to the stamen in _Ophrys aranifera_, _Odontoglossum_, _sp_. &c. It is the ordinary condition in _Gongora_ and some other genera. I have seen it also in _Lilium lancifolium_. Some forms of _Crocus_, occasionally met with, present a very singular appearance, owing to the adhesion of the stamens to the outer segments of the perianth, the former, moreover, being partially petaloid in aspect. M. de la Vaud[35] speaks of a similar union in _Tigridia pavonia_. Morren[36] describes a malformation of _Fuchsia_ wherein the petals were so completely adherent to the stamens, that the former were dragged out of their ordinary position, so as to become opposite to the sepals; the fusion was here so complete that, no trace of it could be seen externally. It should be remarked that it was the outer series of stamens that were thus fused.[37] [Illustration: FIG. 12.--_Crocus._ Adhesion of petaloid stamens to perianth.] =Adhesion of stamens to pistils.=--The stamens also may be united to the pistils, as in gynandrous plants. Moquin speaks of such a case in a _Scabious_; M. Clos in _Verbascum australe_.[38] I have seen cases of the same kind in the Wallflower, Cowslip (_Primula veris_), Tulip, Orange, in the garden Azalea and other plants. =Miscellaneous adhesions.=--Sometimes organs, comparatively speaking, widely separated one from the other, become united together. Miquel has recorded the union of a stigma with the middle lobe of the lower lip of the corolla of _Salvia pratensis_.[39] In the accompanying figure [fig. 13], taken from a double wallflower, there is shown an adhesion between a petal and an open carpel on the one side, and a stamen on the other. Moquin speaks of some pears, which were united, at an early stage, with one or two small leaves borne by the peduncle and grafted to the fruit by the whole of their upper surface. As the pear increased in size the leaves became detached from it, leaving on the surface of the fruit an impression of the same form as the leaf, and differing in colour from the rest of the surface of the fruit. Traces of the principal nerves were seen on the pear. [Illustration: FIG. 13.--_Cheiranthus cheiri_. Adhesion of petal to stamen and open carpel.] It is curious to notice how very rare it is for the calyx to adhere to the ovary in flowers where that organ is normally superior. The "_calyx inferus_" seems scarcely ever to become "_calyx superus_," while, on the other hand, the "_calyx normaliter superus_" frequently becomes inferior from detachment from, or from want of union with the surface of the ovary. =Adhesion of fruit to branch.=--Of this Mr. Berkeley[40] cites an instance in a vegetable marrow (_Cucumis_), where a female flower had become confluent with the branch, at whose base it was placed, and also with two or more flowers at the upper part of the same branch, so as to make an oblique scar running down from the apex of the fruit to the branch. =Synanthy.=--Adhesion of two or more flowers takes place in various ways; sometimes merely the stalks are united together, so that we have a single peduncle, bearing at its extremity two flowers placed in approximation very slightly adherent one to the other. In this manner I have seen three flowers of the vegetable marrow on a common stalk, the flowers themselves being only united at the extreme base. Occasionally cases may be met with wherein the pedicels of a stalked flower become adherent to the side of a sessile flower. I have noticed this commonly in _Umbelliferæ_. Union of this kind occurs frequently in the common cornel (_Cornus_), wherein one of the lower flowers becomes adherent to one of the upper ones. In De Candolle's 'Organographie Végétale,' Plates 14 and 15, are figured cases of fusion of the flower stems of the Hyacinth and of a _Centaurea_. In other cases the union involves not only the stalk but the flowers themselves; thus fusion of the flowers is a common accompaniment of fasciation, as was the case in the _Campanula_ figured in the cut (fig. 14). [Illustration: FIG. 14.--Synanthic flowers of _Campanula medium_.] Synanthy may take place without much derangement of the structure of either flower, or the union may be attended with abortion or suppression of some of the parts of one or both flowers. Occasionally this union is carried to such an extent that a bloom appears to be single, when it is, in reality, composed of two or more, the parts of which have become not only fused, but, as it were, thrust into and completely incorporated one with another, and in such a manner as to occupy the place of some parts of the flower which have been suppressed. It must not be overlooked that this adhesion of one flower to another is a very common occurrence under natural circumstances, as in _Lonicera_, in the common tomato, in _Pomax_, _Opercularia_, _Symphyomyrtus_, &c., while the large size of some of the cultivated sunflowers is in like manner due to the union of two or more flower-heads. One of the simplest instances of synanthy is that mentioned by M. Duchartre,[41] in which two flowers of a hyacinth were united together simply by means of two segments of the perianth one from each flower. A similar occurrence has been cited by M. Gay in _Narcissus chrysanthus_. In like manner the blossoms of Fuchsias or Loniceras occasionally become adherent merely by their surface, without involving any other change in the conformation of the flowers. M. Maugin alludes to a case of this kind in _Aristolochia Clematitis_.[42] But it is more usual for some of the organs to be suppressed, so that the number of existing parts is less than would be the case in two or more uncombined flowers. A few illustrations will exemplify this. In two flowers of _Matthiola incana_, that I observed to be joined together, there were eight sepals, eight petals, and ten perfect stamens, eight long and two short, instead of twelve. Closer examination showed that the point of union between the two flowers occurred just where, under ordinary circumstances, the two short stamens would be. In this instance but little suppression had occurred. In similar flowers of _Narcissus incomparabilis_ I remarked a ten-parted perianth, ten stamens within a single cup, two styles, and a five-celled ovary. Here, then, it would appear that two segments of the perianth, two stamens, and one carpel were suppressed. In a Polyanthus there were nine sepals, nine petals, nine stamens, and a double ovary. [Illustration: FIG. 15.--Union of three flowers of _Calanthe vestita_.] [Illustration: FIG. 16.--Shows the abortion of the central spur in synanthic flowers of _Calanthe vestita_.] As an illustration of a more complicated nature reference may be made to three flowers of _Aconitum Napellus_, figured by A. de Chamisso, 'Linnæa,' vol. vii, 1832, p. 205, tab. vii, figs. 1, 2. In this specimen the two outer blossoms had each four sepals present, namely, the upper hooded one, one of the lateral sepals, and both of the inferior ones; the central flower had only the upper sepal and one other, probably one of the lower sepals; thus there were but ten sepals instead of fifteen. The nectary-like petals, the stamens, and pistils were all present in the lateral flowers, but were completely suppressed in the middle one. A less degree of suppression was exemplified in a triple flower of _Calanthe vestita_ sent me by Dr. Moore, of Glasnevin, in which all the parts usually existing in three separate flowers were to be found, with the exception of the spur belonging to the labellum of the middle flower (figs. 15, 16). One of the most common malformations in the Foxglove (_Digitalis_) results from the fusion of several of the terminal flowers into one. In these cases the number of parts is very variable in different instances; the sepals are more or less blended together, and the corollas as well as the stamens are usually free and distinct, the latter often of equal length, so that the blossom, although truly complex, is, as to its external form, less irregular than under natural circumstances. The centre of these flowers is occupied by a two to five-celled pistil, between the carpels of which, not unfrequently, the stem of the plant projects, bearing on its sides bracts and rudimentary flowers. (See Prolification.) An instance of this nature is figured in the 'Gardeners' Chronicle,' 1850, p. 435, from which the cut (fig. 17) is borrowed. [Illustration: FIG. 17.--Synanthy and other changes in a Foxglove.] One of the most singular recorded instances of changes connected with fusion of the flowers is that cited by Reinsch,[43] where two female flowers of _Salix cinerea_ were so united with a male one as to produce an hermaphrodite blossom. It follows, from what has been said, that the number of parts that are met with in these fused flowers varies according to the number of blossoms and of the organs which have been suppressed. Comparatively rarely do we find all the organs present; but when two flowers are united together we find every possible variety between the number of parts naturally belonging to the two flowers and that belonging to a single one. Sometimes instances are met with wherein the calyx does not present the normal number of parts, while the other parts of the flower are in excess. I have seen in a _Calceolaria_ a single calyx, with the ordinary number of sepals, enclosing two corollas, adherent simply by their upper lips, and containing stamens and pistils in the usual way. In this instance, then, the sepals of one flower must have been suppressed, while no such suppression took place in the other parts of the flower. Professor Charles Morren paid special attention to the various methods in which the flowers of Calceolarias may become fused, and to the complications that ensue from the suppression of some parts, the complete amalgamation of others, &c. Referring the reader to the Belgian savant's papers for the full details of the changes observed, it is only necessary to allude to a few of the most salient features. [Illustration: FIG. 18.--Synanthic flowers of Calceolaria in which, with two upper lips, there was but a single lower one.] Sometimes the upper lips of two flowers are fused into one, the two lower remaining distinct. In other cases, the upper lip disappears altogether, while there are two lower lips placed opposite one another;, of the stamens, sometimes the outermost, at other times the innermost disappear.[44] Occasionally there appears to be, as it were, a transference of the parts of one flower to another. One of the simplest and most intelligible cases of this kind is recorded by Wigand in the 'Flora' for 1856, in a compound flower of _Polygonatum anceps_, in which within a twelve-parted perianth there were twelve stamens and two pistils, one four-celled, the other two-celled; hence it would appear as if a carpel belonging to one flower had become united to those constituting the pistil of the adjacent one. Among Orchids this fusion of some of the elements of different flowers, together with the suppression of others, is carried to such an extent as to render the real structure difficult to decipher. Sometimes flowers of _Ophrys aranifera_, at first sight seeming normal as to the number, and almost so as regards the arrangement of their parts, have yet, on examination, proved to be the result of a confluence of two flowers. Mr. Moggridge has observed similar phenomena in the same species at Mentone. Sometimes the fusion affects flowers belonging to different branches of the same inflorescence, as in _Centranthus ruber_, described by Buchenau, 'Flora,' 1857, p. 293, and even a blossom of one generation of axes may be united with a flower belonging to another generation. Thus M. Michalet[45] speaks of a case wherein the terminal flower of _Betonica alopecuros_ was affected with Peloria, and fused with an adjacent one belonging to a secondary axis of inflorescence, and not yet expanded. This latter flower had no calyx, but in its place were three bracts, surrounding the corolla; this again was united to the calyx of the terminal bloom in a most singular manner, the limb of the corolla and that of the calyx being so joined one to the other as to form but a single tube. It is not uncommon, as has been before stated, to find two corollas enclosed within one calyx, but this is probably the only recorded instance of the fusion of the calyx and corolla of two different flowers belonging to two different axes. From the preceding details, as well as from others which it is not necessary to give in this place, it would appear that synanthy is more liable to occur where the flowers are naturally crowded together[46] than where they are remote; so too, the upper or younger portions of the inflorescence are those most subject to this change. In like manner the derangements consequent on the coalescence of flowers are often more grave in the central organs, which are most exposed to pressure, and have the least opportunities of resisting the effects of that agency, than they are in the outer portions of the flowers where growth is less restricted. Morren in his papers on synanthic _Calceolarias_, before referred to, considers that the direction in which fusion acts is centripetal, _e.g._ from the circumference towards the centre of the flower, thus reversing the natural order of things. He considers that there is a radical antagonism between the normal organizing forces and the teratological disorganizing forces, and explains in this way the frequent sterility of monsters from an imperfect formation of stamens, or pistils, or both. The greater tendency in synanthic flowers of parts of one whorl to adhere to the corresponding organs in another flower has often been remarked, though the dislocation of parts may be so great as to prevent this from being carried out in all cases. It appears also that synanthy is more frequently met with among flowers which have an inferior ovary than in those in which the relative position of the organ in question is reversed. This remark applies particularly to individual cases; the proportion as regards the genera may not be so large. The explanation of this must of course depend on the circumstances of each particular case; and it would be wrong to attempt to lay down a general rule, when organogenists have not yet fully decided in what plants the inferior ovary is an axial structure, and in what others the appearance is due to the adhesion of the base of the calyx to the carpels. The list which follows is not intended as a complete one, but it may serve to show what plants are more particularly subject to this anomaly; the * indicates unusual frequency of occurrence, the ! signifies that the writer has himself seen instances in the plants named. Many of the recorded cases of Synanthy are really cases of adhesion of the inflorescence rather than of the flowers. Ranunculus Lingua. bulbosus! Aconitum Napellus. Delphinium sp.! Matthiola incana! Arabis sagittata. Silene sp. Reseda odorata! Vitis vinifera. Citrus aurantium. *Fuchsia var. hort.! OEnothera sp. Saxifraga sp. Podalyria myrtillifolia. Prunus Armeniaca. spinosa. Pyrus Malus. Persica vulgaris. Cratægus monogyna. Robinia pseudacacia. Gleditschia triacanthos. Syringa persica. Cornus sanguinea. Viburnum sp. *Lonicera sp. plur! Centranthus ruber! Valantia cruciata. Centaurea moschata. Jacea. Zinnia elegans. Zinnia revoluta. Helianthus sp.! Spilanthes oleracea. Dahlia. *Leontodon Taraxacum! Senecio Doria. Cichorium Intybus. Lactuca sativa. Anthemis retusa. *Campanula medium! persicifolia. Azalea indica! Vinca minor. Atropa Belladonna. *Solanum Lycopersicum! *Petunia violacea! Galeopsis ochroleuca. Betonica alopecuros. *Digitalis purpurea! *Antirrhinum majus! *Linaria purpurea! *Pedicularis sylvatica! *Calceolaria var. hort.! Scrophularia nodosa. Salpiglossis straminea. Streptocarpus Rexii. *Gesnera var. hort.! Æschynanthus sp.! Thyrsacanthus rutilans! Anagallis collina. *Primula veris! Auricula. *Primula acaulis, var. umbellata! elatior? * sinensis! Aristolochia Clematitis. Blitum sp. Chenopodium sp. Rumex sp. Salix cinerea. *Hyacinthus orientalis! Lilium bulbiferum! croceum, et sp. alix, pl. Tulipa, sp. Polygonatum anceps. Fritillaria imperalis! Agave americana. Iris versicolor. sambucina. Crocus, sp. Colchicum autumnale. Narcissus incomparabilis! Tazetta. biflorus. chrysanthus. *Ophrys aranifera! Calanthe vestita! Oncidium bicolor. ornithorhyncum. &c. &c. In addition to the works before cited, additional information on this subject may be gained from the following:--Jaeger, 'Missbilld.,' p. 92. v. Schlechtend, 'Bot. Zeit.,' 1856, _Robinia_. Weber, 'Verhandl. Nat. Hist. Vereins. Preuss. Rheinl.,' 1849, p. 290, _Primula_. Hincks, 'Rep. Brit. Assoc. Newcastle,' 1838, _Salpiglossis_. Clos, 'Mém. Acad. Toulouse,' vol. vi, 1862, _Anagallis_. Wigand, 'Flora,' 1856, tab. 8, _Pedicularis_. Henfrey, 'Botan. Gazette,' i, p. 280, _Reseda_. P. Reinsch, 'Flora,' 1860, tab. 7, _Petasites_. Weber, Verhandl. Nat. Hist. Vereins. f.d. Preuss. Rheinl. u. Westphal.,' 1860, p. 332, tabs. 6 et 7, _Prunus_, _Persica_, _Campanula_, _Taraxacum_, _Saxifraga_, _Silene_, _Hyacinthus_, _&c._ Miquel, 'Linnæa,' xi, p. 423, _Colchicum_. Michel, 'Traité du Citronnier,' tab. 6, _Citrus_. =Syncarpy.=--In the preceding section it has been shown that the carpels, like other parts of the flower, are subject to be united together. This union may either take place between the carpels of a single flower or between the pistils of different flowers. In the latter case the other floral whorls are generally more or less altered. Where, however, the ovary is, as it is called, inferior, it may happen that the pistils of different flowers may coalesce more or less without much alteration in the other parts of the flower, as happens normally in many _Caprifoliaceæ_, _Rubiaceæ_, &c. &c. In some of these cases it must be remembered that the real structure of the apparent fruit is not made out beyond dispute, the main points of controversy being as to what, if any, share the dilated fruit-stalk or axis takes in the formation of such organs. Again, it will be borne in mind that in some cases the so-called fruit is made up of a number of flowers all fused together, as in the Mulberry or the Pineapple, in which plants what is, in ordinary language, called the fruit really consists of the whole mass of flowers constituting the inflorescence fused together. Union of the fruits may also in some cases take place between the carpels after the fall of the other floral whorls, particularly when the outer layers of the pericarp assume a succulent condition, so that under the general head of syncarpy really different conditions are almost necessarily grouped together, and, in seeking to investigate the causes of the phenomenon, the particular circumstances of each individual case must be taken into account. Syncarpy takes place in various degrees; sometimes only the stalks are joined; at other times the whole extent of the fruit, as in cherries, &c. This peculiarity did not escape the observant mind of Shakespeare-- "A double cherry seeming parted. But yet a union in partition, Two lovely berries moulded on one stem." 'Midsummer Night's Dream,' act iii, sc. 2. A similar union has been observed in peaches, gooseberries, gourds, melons, and a great many other fruits. In the Barbarossa grape I have frequently seen a fusion of two, three, four or more berries quite at the end of the bunch, so that the clusters were terminated by a compound grape. Seringe has remarked sometimes two, sometimes three, fruits of _Ranunculus tripartitus_ soldered together. He has also seen three melons similarly joined.[47] Turpin mentions having seen a complete union between the three smooth and leathery pericarps which are naturally separate and enclosed within the spiny cupule of the chestnut.[48] Poiteau and Turpin have figured and described in their treatise on fruit trees, under the name of Néfle de Correa, four or five medlars, joined together and surmounted by all the persistent leaflets of the calyces.[49] A very remarkable example of Syncarpy has been recorded by E. Koenig in which nine strawberries were borne on one stem (_Fragaria botryformis_),[50] and a similar malformation has been observed in the Pineapple. When two fruits are united together they may be of about equal size, while in other cases one of the two is much smaller than the other. This was the case in two cucumbers given to me by Mr. James Salter. These were united together along their whole length excepting at the very tips; the upper one of the two was much larger than the lower, and contained three cells, the lower fruit was one-celled by suppression. Both fruits were curved, the curvature being evidently due to the more rapid growth of the upper as compared with the lower one. [Illustration: FIG. 19.--Adhesion of two apples.] [Illustration: FIG. 20.--Section of united apples.] In many of these cases, where the fruits are united by their bases, the summits become separated one from the other, so as to resemble the letter V. Such divergence is of frequent occurrence where fruits are united by their stalks, because, as growth goes on, the tendency must necessarily be towards separation and divergence of the tips of the fruit. In some cases of Syncarpy the fusion and interpenetration of the carpels is carried to such an extent that it is very difficult to trace on the outer surface the lines of union. The fruit in these cases resembles a single one of much larger size than usual. Moquin mentions a double apple in which the connection was so close that the fruit was not very different in form from what is customary, and a similar thing happens with the tomato. In the case of stone-fruits it sometimes happens, not only that the outer portions are adherent, but that the stones are so likewise. M. Roeper has observed two apples grafted together, one of which had its stalk broken, and seemed evidently borne and nourished by the other apple;[51] and a similar occurrence happens not infrequently in the cucumber. Moquin has seen three united cherries having only a single stalk jointed to the central fruit, the lateral cherries having each a slight depression or cicatrix marking the situation of the suppressed stalks. Schlotterbec has figured three apples presenting precisely similar appearances.[52] Fusion of two or more nuts (_Corylus_) is not uncommon; I have seen as many as five so united.[53] In these cases the fruits may be united together in a ring or in linear series. In some _Leguminosæ_, contrary to the general rule in the order, more than one carpel is found; thus peas, French beans, and other similar plants, are occasionally met with having two or more pods within the same calyx, and in _Gleditschia triacanthos_ and _Cæsalpinia digyna_ this is so commonly the case as to be considered almost the normal state. (De Cand. 'Mem. Leg.,' pl. 2, fig. 6; pl. 3, fig. 2.) At times these carpels become fused together, and it becomes difficult, when the traces of the flower have disappeared, to ascertain whether these carpels were formed in one flower, or whether they were the result of the fusion of several blossoms. I have seen an instance of this kind in a plum in which there were two carpels in the same flower, the one being partially fused to the other. The nature of such cases may usually be determined by an inspection of the peduncle which shows no traces of fusion. (See chapter on Multiplication.) When, however, the fruits are sessile, and they become grafted together, the kind of syncarpy is difficult to distinguish. It, may, nevertheless, be said as a general rule that the union brought about by the approximation of two fruits, after the fall of the floral whorls, is never so complete or so intimate as that determined by synanthy; and also that in those cases where there are supernumerary carpels in the flower, and those carpels become united together, they are rarely so completely fused that their individuality is lost. An analogous phenomenon takes place not uncommonly in mosses, the spore capsules of which become united together in various ways and degrees. Schimper[54] cites the following species as subject to this anomaly:--_Buxbaumia indusiata_, _Leskea sericea_, _Hypnum lutescens_, _Anomodon alternatus_, _Clinacium dendroides_, _Bryum cæspititium_, _Brachythecium plumosum_, _Mnium serratum_, _Splachnum vasculosum_. It has also been observed in _Trichostomum rigidulum_ and _Hypnum triquetrum_. In addition to the authorities already mentioned, the reader may consult Moquin-Tandon, 'El. Ter. Veg.,' p. 270. Turpin. 'Mém. greffe. Ann. Sc. Nat.,' ser. i, t. xxiv, p. 334. De Candolle, 'Organ. Veget.,' t. i. Duhamel, 'Phys. des Arbres,' t. i, p. 304, tab. xiii, xiv. Weber. 'Verhandl. Nat. Hist. Vereina f. d. Preuss. Rheinl. u. Westphal.,' 1860, p. 332, tab. vi. et vii. =Synspermy, or Union of the Seeds.=--Seeds may be united together in various degrees, either by their integuments,[55] or by their inner parts. Such union of the seeds, however, is of rare occurrence. It takes place normally, to a slight extent, in certain cultivated forms of cotton, wherein the seeds are aggregated together into a reniform mass, whence the term kidney cotton. Union of the parts of the embryo is treated under another head (see Synophty). =Adhesion between the axes of different plants.=--Under this head may be classed the union that takes place between the stems, branches, or roots of different plants of the same species, and that which occurs between individuals of different species; the first is not very different in its nature from cohesion of the branches of the same plant (figs. 21, 22). It finds its parallel, under natural circumstances, among the lower cryptogams, in which it often happens that several individual plants, originally distinct, become inseparably blended together into one mass. In the gardening operations of inarching, and to some extent in budding, this adhesion of axis to axis occurs, the union taking place the more readily in proportion as the contact between the younger growing portions of the two axes respectively is close. The huge size of some trees has been, in some cases, attributed to the adnation of different stems. This is said to be the case with the famous plane trees of Bujukdere, near Constantinople, and in which nine trunks are more or less united together.[56] [Illustration: FIG. 21.--Adhesion of two distinct stems of oak, or possibly cohesion of branches of the same tree. 'Gard. Chron.,' 1846, p. 252.] A similar anastomosis may take place in the roots. Lindley cites a case wherein two carrots, of the white Belgian and the red Surrey varieties respectively, had grown so close to each other that each twisted half round the other, so that they ultimately became soldered together; the most singular thing with reference to this union was, that the red carrot (fig. 23, _b_), with its small overgrown part above the junction, took the colour and large dimensions of the white Belgian (_d_), which, in like manner, with its larger head above the joining (_a_), took the colour and small dimensions of the red one at and below the union (_e d_). The respective qualities of the two roots were thus transposed, while the upper portions or crowns were unaffected: the root of one, naturally weak, became distended and enlarged by the abundant matter poured into it by its new crown; and in like manner the root of the other, naturally vigorous, was starved by insufficient food derived from the new crown, and became diminutive and shrunken (see Synophty). [Illustration: FIG. 22.--Adhesion of the branches of two elms. 'Gard. Chron.,' 1849, p. 421.] The explanation of the fact that the stumps of felled fir trees occasionally continue to grow, and to deposit fresh zones of wood over the stump, depends on similar facts. In _Abies pectinata_, says Goeppert,[57] the roots of different individuals frequently unite; hence if one be cut down, its stump may continue to live, being supplied with nourishment from the adjacent trees to which it is adherent by means of its roots. [Illustration: FIG. 23.--Adhesion of two roots of carrot. 'Gard. Chron.,' 1851, p. 67.] A not uncommon malformation in mushrooms arises from the confluence of their stalks (fig. 24), and when the union takes place by means of the pilei, it sometimes happens, during growth, that the one fungus is detached from its attachment to the ground, and is borne up with the other, sometimes, even, being found in an inverted position on the top of its fellow.[58] The garden operations of budding, grafting and inarching have already been alluded to as furnishing illustrations of adhesion, but it may be well to refer briefly to certain other interesting examples of adhesion induced artificially; thus, the employment of the root as a stock, "root-grafting," is now largely practised with some plants, as affording a quicker means of propagation than by cuttings; and a still more curious illustration may be cited in the fact that it has also been found possible to graft a scion on the leaf in the orange.[59] [Illustration: FIG. 24.--Section through two adherent mushrooms, the upper one inverted.] Mr. Darwin, in his work on the 'Variation of Animals and Plants,' vol. i, p. 395, alludes to the two following remarkable cases of fusion:--"The author of 'Des Jacinthes' (Amsterdam, 1768, p. 124) says that bulbs of blue and red hyacinths may be cut in two, and that they will grow together, and throw up a united stem (and this Mr. Darwin has himself seen), with flowers of the two colours on the opposite sides. But the remarkable point is, that flowers are sometimes produced with the two colours blended together." In the second case related by Mr. Trail, about sixty blue and white potatoes were cut in halves through the eyes or buds, and the halves were then joined, the other buds being destroyed. Union took place, and some of the united tubers produced white, others blue, while some produced tubers partly white and partly blue. =Adhesion of the axes of plants belonging to different species is a= more singular occurrence than the former, and is of some interest as connected with the operation of grafting. As a general rule horticulturists are of opinion, and their opinion is borne out by facts, that the operation of grafting, to be successful, must be practised on plants of close botanical affinity. On the other hand, it is equally true that some plants very closely allied cannot be propagated in this manner. Contact between the younger growing tissues is essential to successful grafting as practised by the gardener, and is probably quite as necessary in those cases where the process takes place naturally. Although there is little doubt but that some of the recorded instances of natural or artificial grafting of plants of distant botanical affinities are untrustworthy, yet the instances of adhesion between widely different plants are too numerous and too well attested to allow of doubt. Moreover, when parasitical plants are considered, such as the Orobanches, the Cuscutas, and specially the mistleto (_Viscum_), which may be found growing on plants of very varied botanical relationship, the occurrence of occasional adhesion between plants of distant affinity is not so much to be wondered at. Union between the haulms of wheat and rye, and other grasses, has been recorded[60]. Moquin-Tandon[61] relates a case wherein, by accident, a branch of a species of _Sophora_ passed through the fork, made by two diverging branches of an elder (_Sambucus_), growing in the Jardin des Plantes of Toulouse. The branch of the _Sophora_ contracted a firm adhesion to the elder, and what is remarkable is that, although the latter has much softer wood than the former, yet the branch of the harder wooded tree was flattened, as if subjected to great pressure[62]. It is possible that some of the cases similar to those spoken of by Columella, Virgil[63], and other classical writers, may have originated in the accidental admission of seeds into the crevices of trees; in time the seeds grew, and as they did so, the young plants contracted an adhesion to the supporting tree. Some of the instances recorded by classical writers may be attributed to intentional or accidental fallacy, as in the so-called "greffe des charlatans" of more modern days. Adhesion of the roots of different species has been effected artificially, as between the carrot and the beet root, while Dr. Maclean succeeded in engrafting, on a red beet, a scion of the white Silesian variety of the same species. In all these cases, even in the most successful grafts, the amount of adhesion is very slight; the union in no degree warrants the term fusion, it is little but simple contact of similar tissues, while new growing matter is formed all round the cut surfaces, so that the latter become gradually imbedded in the newly formed matter. =Synophty or adhesion of the embryo.=--This often occurs partially in the embryo plants of the common mistleto (_Viscum_), but is not of common occurrence in other plants, even in such cases as the orange (_Citrus_), the _Cycadeæ_, _Coniferæ_, &c., where there is frequently more than one embryo in the seed. Alphonse De Candolle has described and figured an instance of the kind in _Euphorbia helioscopia_, wherein two embryo plants were completely grafted together throughout the whole length of their axes, leaving merely the four cotyledons separate. A similar adnation has been observed by the same botanist in _Lepidium sativum_ and _Sinapis ramosa_, as well as in other plants.[64] I have met with corresponding instances in _Antirrhinum majus_ and in _Cratægus oxyacantha_, in the latter case complicated with the partial atrophy of one of the four cotyledons. It is necessary to distinguish between such cases and the fallacious appearances arising from a division of the cotyledons. M. Morren has figured and described the union of two roots of carrot (_Daucus_), which were also spirally twisted. He attributes this union to the blending of two radicles, and applies the term "rhizocollesy" to this union of the roots.[65] Mr. Thwaites cites a case wherein two embryos were contained in one seed in a _Fuchsia_, and had become adherent. What is still more remarkable, the two embryos were different, a circumstance attributable to their hybrid origin, the seed containing them being the result of the fertilisation of _Fuchsia coccinea_ (quere _F. magellanica?_) by the pollen of _F. fulgens_. FOOTNOTES: [30] Wydler, 'Flora,' 1852, p. 737, tab. ix. [31] 'El. Ter. Veg.,' p. 254. [32] 'Bull. Soc. Bot. Fr.,' 1857, p. 451. [33] 'Bull. Acad. Belg.,' vol. xix, part ii, p. 335. [34] 'Bull. Soc. Bot. Fr.,' 1860, p. 25. [35] 'Bull. Soc. Bot. Fr.,' 1861, p. 147. [36] 'Bull. Acad. Belg.,' vol. xviii, part ii, p. 498. [37] See also Prillieux, 'Bull. Soc. Bot. Fr.,' 1861, p. 195. [38] 'Mém. Acad. Toulouse,' 5th Series, vol. iii. [39] Linnæa, vol. ii. p. 607. [40] 'Journal Roy. Hort. Soc.,' new ser., vol. i. 1866, p. 200. [41] 'Bull. Soc. Bot. Fr.,' 1861, p. 159. [42] Ibid., 1859, p. 467. [43] 'Flora,' 1858, p. 65, tab. ii. [44] C. Morren. 'Bull. Acad. Belg.,' vol. xv (Fuchsia, p. 89); vol. xviii, p. 591. (Lobelia, p. 142); vol. xix, p. 352; vol. xx, p. 4. [45] 'Bull. Soc. Bot. Fr.,' vol. vii, p. 625. [46] Cramer, 'Bildungsabweichungen,' p. 56, tab. vii, fig. 10, figures a case wherein the two central flowers of the capitulum of _Centaurea Jacea_ were united together. [47] 'Bull. Bot.' tab. iii, figs. 4-6. [48] 'Mém. greffe Ann. Science Nat.,' ser. i, t. xxiv, p. 334. [49] "Mespilus portentosa." Poit. et Turp., 'Pomol. Franc.,' liv, xxxi, p. 202, pl. 202. [50] Duchesne, 'Hist. Nat. Frais.,' p. 79. [51] De Cand., 'Phys. Végét.,' tom. ii, p. 781. [52] Sched. de monstr. plant. 'Act. Helv.,' tab. i, fig. 8. [53] 'Mém. greffe,' loc. cit., tab. xxiv, p. 334. [54] 'Bull. Soc. Bot. Franc.,' 8, pp. 73 and 351, tab. ii; and Röse. 'Bot. Zeit.,' x, p. 410. [55] _Nymphæa lutea_, _Æsculus Hippocastanum_, &c. See Moquin, 'El. Ter. Veg.,' p. 277. [56] C. Martins, 'Promenade Botanique,' p. 8. [57] 'Ann. Sc. Nat.,' t. xix, 1843, p. 141, tab. iv. [58] 'Ann. Nat. Hist.,' ser. 2, vol. ix, tab. xvi. 'Phytologist,' 1857. p. 352, &c. [59] Quoted from the 'Revue Hortic.' in 'Gard. Chron.,' 1866, p. 386. [60] Senebier, 'Phys Végét.,' t. iv, p. 426. The same author also cites Romer as having found two plants of _Ranunculus_, from the stem of which emerged a daisy. As it is not an uncommon practice to stick a daisy on a buttercup, it is to be hoped no hoax was played off on M. Romer. [61] 'El. Ter. Veg.,' p. 289. [62] An instance of this kind is cited in Dr. Robson's memoir of the late Charles Waterton, from which it appears that two trees, a spruce fir and an elm, were originally planted side by side, and had been annually twisted round each other, so that they had in places grown one into the other, with the result of stunting the growth of both trees, thus illustrating, according to the opinion of the eccentric naturalist above cited, the incongruous union of Church and State! [63] See Daubeny, 'Lectures on Roman Husbandry,' p. 156. [64] A. P. De Candolle, 'Organ Végét.,' t. ii, p. 72, tab. liv, fig. 1. [65] 'Bull. Acad. Belg.,' t. xx, part i, 1852, p. 43. PART II. INDEPENDENCE OR SEPARATION OF ORGANS. Under this head are included all those instances wherein organs usually entire, or more or less united, are, or appear to be, split or disunited. It thus includes such cases as the division of an ordinarily entire leaf into a lobed or partite one, as well as those characterised by the separation of organs usually joined together. Union, as has been stated in a previous chapter, is the result either of persistent integrity or of a junction of originally separate organs, after their formation; so in like manner, the separation or disjunction of parts may arise from the absence of that process of union which is habitual in some cases, or from an actual _bonâ fide_ separation of parts originally united together. In the former case, the isolation of parts arises from arrest of development, while in the latter it is due rather to luxuriant growth. A knowledge, as well of the ordinary as of the unusual course, of development in any particular flower is thus required in order to ascertain with accuracy the true nature of the separation of parts. The late Professor Morren[66] proposed the general term Monosy ([Greek: monôsis]) for all these cases of abnormal isolation, subdividing the group into two, as follows--1, Adesmy ([Greek: a-desmos]), including those cases where the separation is congenital; and 2, Dialysis ([Greek: dialyô]), comprising those instances where the isolation is truly a result of the separation of parts previously joined together. Adesmy, moreover, was by the Belgian savant said to be homologous when it occurred between members of the same whorl, _e.g._ between the sepals of an ordinary monosepalous calyx, or heterologous when the separation took place between members of different whorls, as when the calyx is detached from the ovary, &c. The former case would thus be the converse of cohesion, the latter of adhesion. To the adoption of these words there is this great objection, that we can but rarely, in the present state of our knowledge, tell in which group any particular illustration should be placed. The terms adopted in the present work are, for the most part, not necessarily intended to convey any idea as to the organogenetic history of the parts affected. Where a single organ, that is usually entire, becomes divided the term Fission is used; in cases where parts of the same whorl become isolated, the word Dialysis is employed, and in the same sense in which it is generally used by descriptive botanists, and where the various whorls become detached one from the other, the occurrence is distinguished by the application of the term Solution. FOOTNOTES: [66] 'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315. CHAPTER I. FISSION. When an organ becomes divided it receives at the hands of descriptive botanists the appellations cleft, partite, or sect, according to the depth of the division; hence in considering the teratological instances of this nature, the term fission has suggested itself as an appropriate one to be applied to the subdivision of an habitually entire or undivided organ. It thus corresponds pretty nearly in its application with the term Chorisis or "dédoublement," or with the "disjonctions qui divisent les organes" of Moquin-Tandon.[67] It is usually, but not always, a concomitant with hypertrophy, and dependent on luxuriance of growth. It must be understood therefore that the term, as generally applied, does not so much indicate the cleavage of a persistent organ, as it does the formation and development of two or more growing points instead of one, whence results a branching or forking (di-tri-chotomy) of the affected organ. In some instances it seems rather to be due to the relative deficiency of cellular, as contrasted with fibro-vascular tissue. =Fission of axile organs.=--This condition is scarcely to be distinguished from multiplication of the axile organs (which see). A little attention, however, will generally show whether the unusual number of branches is a consequence of the development of a large number of distinct shoots, as happens, for instance, when a tree is pollarded, or of a division of one. M. Fournier[68] gives as an illustration the case of a specimen of _Ruscus aculeatus_ in which there occurred a division of the foliaceous branches into two segments, reaching as far as the insertion of the flower, but no further. He also mentions lateral cleavage effected by a notching of the margin, the notch being anterior to the flowers and always directed towards their insertion. In the allied genus _Danaë_, Webb, 'Phyt. Canar.,' p. 320, describes the fascicles of flowers as in "crenulis brevibus ad marginem ramulorum dispositis." Sometimes, on the other hand, _Danaë_ has a fascicle of flowers inserted on the middle of the upper surface, as in _Ruscus_. Wigand mentions an instance in _Digitalis lutea_, where the upper part of the stem was divided into six or seven racemes; possibly this was a case of fasciation, but such a division of the inflorescence is by no means uncommon in the spicate species of _Veronica_. I have also seen it in _Plantago lanceolata_, _Reseda luteola_, _Campanula medium_, _Epacris impressa_, and a bifurcation of the axis of the spikelet within the outer glumes in _Lolium perenne_[69] and _Anthoxanthum odoratum_. In the Kew Museum is preserved a cone of _Abies excelsa_,[70] dividing into two divisions, each bearing bracts and scales. A similar thing frequently occurs in the male catkins of _Cedrus Libani_ (fig. 25). [Illustration: FIG. 25.--Bifurcated male inflorescence, _Cedrus Libani_.] This subdivision of axial organs is not unfrequently the result of some injury or mutilation, thus Duval Jouve alludes to the frequency with which branched stems are produced in the various species of _Equisetum_, as a consequence of injuries to the main stem, but this is rather to be considered as a multiplication of parts than as a subdivision of one. [Illustration: FIG. 26.--Bifurcated leaf of _Lamium album_, &c.] =Fission of foliar organs.=--Many leaves exhibit constantly the process of fission, such as the _Salisburia adiantifolia_, and which is due perhaps as much to the absence or relatively small proportion of cellular as compared with vascular tissue, as to absolute fission. In the same way we have laciniated leaves of the Persian lilac, _Syringa persica_, and Moquin mentions instances in a species of _Mercurialis_ in which the leaves were deeply slashed. In _Chenopodium Quinoa_ the leaves were so numerous and the clefts so deep, that the species was hardly recognisable, while on a branch of _Rhus Cotinus_ observed by De Candolle the lobes were so narrow and so fine as to give the plant the aspect of an _Umbellifer_. Wigand ('Flora,' 1856, p. 706) speaks of the leaves of _Dipsacus fullonum_ with bi-partite leaves; Moquin mentions the occurrence of a leaf of an oleander bi-lobed at the summit, so as to give the appearance of a fusion of two leaves. Steinheil has recorded an instance in _Scabiosa atropurpurea_ in which one of the stem leaves presented the following peculiarities. It was simple below, but divided above into two equal lobes, provided each with a median nerve.[71] Steinheil has also recorded a _Cerastium_ in which one of the leaves was provided with two midribs; above this leaf was a group of ternate leaves. I have seen similar instances in the common Elm, _Ulmus campestris_, and also in the common nettle, _Urtica dioica_, the leaves of which latter thus resembled those of _Urtica biloba_, which are habitually bilobed at the summit. M. Clos[72] mentions an instance where the terminal leaf and first bract of _Orchis sambucina_ were divided into two segments. The same author also mentions the leaves of _Anemiopsis californica_, which were divided in their upper halves each into two lobes--also leaves of a lentil springing from a fasciated stem and completely divided into two segments, but with only a single bud in the axil. The axillary branches in like manner showed traces of cleavage. Fig. 26 represents a case of this kind in _Lamium album_, conjoined with suppression of the flowers on one side of the stem. I have also in my herbarium a leaf of _Arum maculatum_, with a stalk single at the base, but dividing into two separate stalks, each bearing a hastate lamina, the form of which is so perfect that were it not from the venation of the sheath it would be considered that there was here a union of two leaves rather than a bifurcation of one. A garden Pelargonium presented the same appearance. [Illustration: FIG. 27.--Bifurcated leaf of _Pelargonium_.] Fern fronds are particularly liable to this kind of subdivision, and they exhibit it in almost every degree, from a simple bifurcation of the frond to the formation of large tufts of small lobes all formed on the same plan by the repeated forking of the pinnules. These may be considered as cases of hypertrophy. Moquin-Tandon, at a meeting of the Botanical Society of France (April 3rd, 1858) exhibited a leaf of _Cerasus Lauro-Cerasus_ divided in such a manner as to resemble a leaf of _Citrus_ or of _Phyllarthron_. In this case, therefore, the disunion must have taken place laterally, and not from apex towards base, as is most common. The leaves of the common horse-radish, _Cochlearia Armoracia_, are very subject to this pinnated subdivision of the margin, and numerous other illustrations might be given. [Illustration: FIG. 28.--Bifurcated frond, _Scolopendrium vulgare_.] A. Braun describes a singular case in a leaf of _Irina glabra_ wherein the blade of the leaf on one side was deeply and irregularly laciniated, the other side remaining entire. (Verhandl., d. 35, Naturforscherversammlung, tab. 3.) Laciniate varieties of plants are of frequent occurrence in gardens where they are often cultivated for their beauty or singularity; thus, there are laciniated alders, fern-leaved beeches and limes, oak-leaved laburnums, &c. A list of several of these is subjoined. A similar fission takes place constantly in the cotyledons of some plants, sometimes, as in _Coniferæ_, to such an extent as to give an appearance as if there were several cotyledons.[73] It is not always easy to recognise, at a first glance, whether the division be the result of disunion or of an incomplete union of two leaves, but we may be guided by the number of leaves in the cycle or the whorl. The number is complete in cases of partial disjunction, while in cases of fusion it is incomplete. Again, in instances of disjunction, there is only one point of origin, but, when two leaves are grafted together, two such points may generally be detected at the base of the leaf, or a transverse section of the leaf-stalk will show indications of fusion. The number and position of the midribs will also serve as a guide, as in cases of fusion there are generally two or more midribs, according to the number of fused leaves; but as Moquin well remarks, this latter character cannot be always depended upon, for the median nerve may divide without any corresponding separation of the cellular portions of the leaf. The author just quoted cites examples of this kind in _Cardamine pratensis_, _Hedera Helix_, _Plantago major_, _Geranium nodosum_. The following list of plants commonly producing leaves that are cleft or divided, to a greater extent than is usual in the species, is mainly taken from one given by Schlechtendal, 'Bot. Zeit.,' 1844, p. 441, with additions from other sources. The ! indicates that the author has himself met with the deviation in question. Many are cultivated as garden varieties under the names here given. Trollius europæus dissectus. Chelidonium majus laciniatum! Glaucium luteum. Brassica oleracea! Tilia parvifolia laciniata. asplenifolia! Acer platanoides laciniatum. crispum. Æsculus Hippocastanum incisum! asplenifolium. Vitis vinifera apiifolia! laciniosa. Ilex Aquifolium! Rhus Toxicodendron quercifolium. Cotinus. Ervum Lens. Cytisus Laburnum quercifolium! incisum. Rubus fraticosus laciniatus! Pyrcis communis. Cerasus Lauro-cerasus. Apium graveolens! Pimpinella magna. Saxifraga. Cratægus Oxyacantha laciniata. quercifolia! Ribes nigrum. Sambucus nigra laciniata! racemosa laciniata. Dipsacus fullonum. Scabiosa atropurpurea! Symphoricarpus racemosus. Helianthus sp.! Lonicera Periclymenum quercifolia! Syringa persica laciniata! Syringa vulgaris! Nerium Oleander! Lamium purpureum. album! Salvia officinalis. Solanum Dulcamara! Fraxinus excelsior crispa. Veronica austriaca. Polemonium cæruleum. Juglans regia laciniata! heterophylla. filicifolia. Anemiopsis californica. Chenopodium Quinoa. Ulmus americana incisa. Fagus sylvatica heterophylla! laciniata! aspleniifolia! incisa. salicifolia! Mercurialis perennis. Urtica dioica. Quercus Cerris laciniata! pubescens filicina. Betula populifolia laciniata. alba dalecarlica. Alnus incana laciniata! glutinosa laciniata! quercifolia. oxyacanthifolia. Corylus Avellana heterophylla! laciniata! urticifolia. Carpinus Betulus incisa! quercifolia. heterophylla. Castanea vesca heterophylla. quercifolia. incisa. Populus alba acerifolia. palmata. quercifolia. balsamifera. Orchis sambucina. Arum maculatum. Filices sp. pl. See also Schlechtendal, 'Bot. Zeit.,' tom. xiii, p. 823. A. Braun, loc. supra citat. For Ferns too numerous for insertion, see Moore, 'Nature-Printed Ferns,' 8vo ed., 2 vols. Clos, 'Mém. Acad. Toulouse,' 1862, p. 51. =Fission of the petals, &c.=--The floral leaves are subject to a similar process of cleavage to that which has just been mentioned as taking place in the leaves. This, indeed, occurs very often as a normal occurrence as in the petals of mignonette (_Reseda_), or those of _Alsine media_ and many other plants. Here, however, we have only to allude to those instances in which the cleavage occurs in flowers whose sepals or petals are usually entire. Under this category Moquin mentions a petal of _Brassica oleracea_ completely split into two. Linné in his 'Flora Lapponica' (pp. 145 and 164) mentions quadrifid petals of _Lychnis dioica_, and much divided petals of _Rubus arcticus_. Among other plants subject to this division of sepals or petals may be mentioned as having come within the writer's personal observation, _Ranunculus Lingua_, _R. acris_, _Papaver somniferum_, and others of this genus, _Saponaria sp._, _Dianthus_, _Narcissus_, &c. In some of the garden varieties of _Cyclamen_ the corolla looks at first sight as if double, and the plan of the flower is oblong or elliptical, instead of circular. In these flowers each lobe of the corolla is divided almost to the base into two lobes, so that there appear to be ten lobes to the corolla instead of five, as usual. The stamens are normal in form and number in these flowers. In the paroquet tulips of gardeners the segments of the perianth are deeply and irregularly gashed, the segments occasionally becoming rolled up and their margins coherent so as to form little tubular spurs. I have also noticed the segments of the perianth in _Crocus_ and _Colchicum_ deeply cleft, so much so sometimes, as to equal in this particular the stigmas. In the flowers of a species of _Oncidium_, communicated to me by Mr. Currey, the lip was divided into three segments perfectly distinct one from the other, but confluent with the column; the two side pieces had callosities at the upper edge close to the base, the central piece had a similar wartlike process in its centre. In these flowers the ovary, the stigma, and the anther were all in a rudimentary condition. Some verbenas raised by Mr. Wills offer a curious illustration of this condition. It will be remembered that some of the lobes or petals of a verbena are normally divided at the base to a slight degree, but in the flowers in question this is carried to such an extent that the enlarged lobes are pushed into the centre of the flower and simulate, at a first glance, a distinct and separate organ, though in reality it is but an enlargement of what occurs normally.[74] [Illustration: FIG. 29.--Flower of _Oncidium sp._ seen from the back. The lip is divided into three unequal segments.] Moquin mentions having seen the stamens of _Matthiola incana_ and _Silene conica_ completely divided, each section bearing half an anther, exactly as happens in _Polygalaceæ_. In tulips and lilies the same author mentions division of the anther only, the filament remaining entire, as happens naturally in many species of _Vaccinium_. A division of the individual carpels occurs very frequently when those organs become more or less leafy, as in _Trifolium repens_, and other plants to be hereafter mentioned. The instances given in this chapter have all been cases wherein the division or the accessory growth has taken place in one plane only and that plane the same as that of the affected organ, but there are other examples, probably equally due to fissiparous division, where the new growth is either parallel to, or even at angle with the primary organ. Of such nature are some of those instances wherein two leaves appear to be placed back to back. These partake of the nature of excrescences or of exaggerated developments, and hence will be more fully treated of under the head of hypertrophy. It must be remembered that in some of these cases the fission may be a resumption of characters proper to the species under natural conditions, but lost by cultivation or otherwise. Thus, Mr. Buckman accounts for "finger-and-toe" in root-crops on the principle of reversion to the wild form. FOOTNOTES: [67] Loc. cit., p. 295. [68] 'Bull. Soc. Bot. France,' 1857, p. 758. [69] Masters, 'Jourl. Linn. Soc.,' vol. vii, p. 121. [70] Cramer, 'Bildungsabweichungen,' p. 4, tab. vi, fig. 4, figures a case of the same kind in _Pinus Cembra_. [71] 'Ann. des Science Nat.,' 2nd series, t. iv, p. 147, tab. v, figs. 3 and 4. [72] 'Mém. Acad. Scien. Toulouse,' 5th series, vol. iii. [73] Duchartre, 'Ann. Sc. Nat.,' 3rd series, 1848, vol. x, p. 207. [74] Masters, 'Rep. Bot. Congress,' London, 1866, p. 136, tab. 7, f. 15, 16. CHAPTER II. DIALYSIS. This term is here made use of in the same sense as in descriptive botany, to indicate the isolation of parts of the same whorl; it is thus the opposite of cohesion. Morren, as has been previously stated, employed the word in a different sense, while Moquin-Tandon[75] included cases of this description under the category of "Disjonctions qui isolent les organes." Dialysis, as here understood, may be the result of an arrest of development, in consequence of which parts that under ordinary circumstances would become fused, do not do so; or, on the other hand, it may be the result of an actual separation between parts primitively undivided. As it is not possible in every case to distinguish between the effects of these two diverse causes, no attempt is here made to do so. =Dialysis of the margins of individual foliar organs.=--In cases where the leaf or leaf-like organ is ordinarily tubular or horn-like in form, owing to the cohesion of its edges, it may happen either from lack of union or from actual separation of the previously united edges, that the tubular shape is replaced by the ordinary flattened expansion. Thus, in _Eranthis hyemalis_, wherein the petals (nectaries) are tubular and the sepals flat, I have met with numerous instances of transition from the one form to the other, as shown in fig. 9, p. 24. It is, however, in the carpels that this separation occurs most frequently. When these organs appear under the guise of leaves, as they often do, their margins are disunited, so that the carpel becomes flat or open. This happens in the strawberry (_Fragaria_), the columbine (_Aquilegia_), in _Trifolium repens_, _Ranunculus Ficaria_, &c.[76] =Dialysis of the parts of the same whorl:--calyx.=--The separation of an ordinarily coherent series into its constituent parts is necessarily of more common occurrence than the foregoing. As here understood, it is the precise converse of cohesion, and it may be represented diagrammatically by a dotted line above the letters denoting the sepals, petals, &c. When this change happens in the calyx we have the gamosepalous condition replaced by the polysepalous one, as thus represented: ............. S S S S S instead of _____________ S S S S S as in a calyx of five coherent sepals. Detachment of this kind occurs not unfrequently, as in _Primula vulgaris_, _Trifolium repens_, &c. In _Rosaceæ_ and _Pomaceæ_ this separation of the calyx is of the more moment, as it has reference to the structure of the inferior ovary, as will be more fully mentioned hereafter. Here, however, a case recorded by M. J. E. Planchon may be alluded to[77] wherein a quince fruit (_Cydonia_) was surmounted by five leaves, the surface of the pome being marked by as many prominences, which apparently corresponded to the five stalks of the calycine leaves. In this specimen, then, the inferior position of the ovary appeared to be not so much due to an expansion of the fruit stalk, as to the fusion of the hypertrophied stalks of the sepals. Some of the malformations among Cucurbits point to a similar structure. It is probable that in many of these cases the so-called inferior ovary is partly axial partly foliar, _i.e._, sepaline, and partly carpellary in its nature. Dialysis of the sepals in calyces that are usually gamosepalous has been most frequently observed in _Rosaceæ_, _Pomaceæ_, _Umbelliferæ_, less commonly in _Leguminosæ_, also in the following genera:--_Primula_, _Symphytum_, _Gentiana_, _Campanula_, &c. [Illustration: FIG. 30.--Dialysis of the sepals and petals in _Correa_.] =Dialysis of the corolla= is likewise of frequent occurrence, either partially or to such an extent as to render the corolla truly polypetalous. Among _Labiatæ_ the upper lip of the corolla may be often met with partially cleft, as it is constantly in _Phlomis biloba_, or more markedly among the _Lobeliaceæ_. In the _Compositæ_, a similar separation of the petals is not infrequent, thus showing frequent transitional stages between the labiatifloral and tubulifloral divisions respectively. The ligulate corollas also may often be found in Chrysanthemums, Dahlias, &c., more or less deeply divided into their component parts. A more complete separation occurs not unfrequently in _Campanula_, _Rhododendron_, _Phlox_, _&c._ Figs. 30 and 31 illustrate dialysis of the corolla; the first in _Correa_, the second in _Campanula_. [Illustration: FIG. 31.--Dialysis of the corolla in _Campanula sp._, after De Candolle.] In the last-named genus, _C. rotundifolia_ has been found with polypetalous flowers in a wild state in the mountains of Canton Neufchatel, Switzerland, and gave rise to the creation of a new genus. This form is now introduced into gardens. It must be remembered that in some genera, where this separation of the petals has been met with, there are species in which a similar isolation occurs normally, as in _Rhododendron_. _R. linearilobum_, a Japanese species, offers a good illustration of this. The following list contains the names of the genera in which this separation of the petals of an ordinarily gamopetalous flower takes place most frequently. Correa. Campanula! sp. pl. Polemonium. Phlox! Coboea! Rhododendron! Erica! Rhodora. Azalea! Compositæ! sp. pl. Lonicera! Convolvulus! Pharbitis. Antirrhinum! Verbascum! Mimulus. Digitalis! Orobanche. Solanum. Nicotiana. Gentiana! Anagallis. Primula! Lamium! Convallaria! Lilium! Colchicum! &c. &c. This list does not include those very numerous cases in which this change is associated with more or less complete frondescence or leafy condition of the petals. =Dialysis of the stamens.=--A similar isolation of the stamens occurs occasionally; for instance, when Mallows (_Malvaceæ_) become double, one of the first stages of the process is often the disjunction of the stamens, and a similar dissociation occurs in _Leguminosæ_ and _Compositæ_, as in _Tragopogon_, as related by Kirschleger, in _Hypochæris_ by Wigand, and in _Coreopsis_ by Schlechtendal. =Dialysis of the carpels.=--In the case of the carpels this disunion is more frequent than in the stamens. M. Seringe[78] figures carpels of _Diplotaxis tenuifolia_ more or less completely separated one from the other; indeed, this separation is very common amongst _Cruciferæ_ and _Umbelliferæ_. Generally speaking, the disunion is complicated with frondescence--but not always so. I have, in my herbarium, specimens of _Convallaria majalis_, _Commelyna sp._, and of _Lilium auratum_, in all of which the three carpels are completely disjoined, and present three styles, three stigmas, &c., without any other change. Engelmann[79] speaks of three classes of this malformation. 1st, that in which the carpels separate one from the other without opening, as in the lily just alluded to; 2nd, that in which the ovary remains closed, but loses its internal partitions, as in a case mentioned by Moquin in _Stachys sylvatica_, in which, owing to imperfect disjunction, the two bi-lobed carpels were changed into a nearly one-celled capsule;[80] and 3rd, those cases in which the carpels are open and foliaceous. [Illustration: FIG. 32.--Anomalous form of orange.] Disjunction is more frequent in dry fruits than in fleshy ones. In the latter instance it happens at an early stage of existence, and the pericarp becomes more or less leafy, losing its faculty of becoming fleshy, as in _Prunus Cerasus_ and _Amygdalus persica_; nevertheless, fleshy fruits sometimes become disunited. I have seen a case similar to that mentioned by M. Alphonse de Candolle in _Solanum esculentum_, in which the pericarp became ruptured, and the placentas protruded. A like occurrence has also been observed in a species of _Melastoma_.[81] This is analogous to what happens in _Caulophyllum_ and _Slateria_. Disjunction of the carpels is not rare in oranges. Sometimes this takes place regularly, at other times irregularly; occasionally in such a manner as to give the appearance of a hand and fingers to the fruit. Of one of these, Ferrari,[82] in the curious volume below cited, speaks thus: "Arbor profusissima, quia dat utraque manu; imo quia vere manus dat in poma conversis; utque magis munifica sit poma ipsa convertit in manus." M. Duchartre[83] mentions a semi-double flower of orange with eight to ten distinct carpels in a whorl, and occasionally several whorls one above another. De Candolle[84] considers the rind of the orange as a production from the receptacle, and this view is confirmed by the specimens of Duchartre, in which the carpels were quite naked or had a common envelope truncated, and open above to allow of the passage of the styles and stigmas. [Illustration: FIG. 33.--Orange. Showing disjunction of carpels, after Maout.] [Illustration: FIG. 34.--Section of orange shown in fig. 33 after Maout.] It frequently happens in conjunction with this separation of the carpels one from the other, that a lack of union manifests itself between the margins of the individual carpels themselves. Very numerous cases of this kind have been recorded, and the double tulips of gardens may be referred to as showing this condition very frequently. In connection with this detachment of the carpels, a change in the mode of placentation is often to be observed, or two or more kinds may be seen in the same pistil, as in double-flowered saponarias, many Crucifers, &c., as alluded to under the head of displacements of the placenta. FOOTNOTES: [75] _Loc. cit._, p. 298. [76] Masters in Seemann's 'Journal of Botany,' 1867, p. 158. [77] Bull. Soc. Bot. France,' t. xiii, 1866, p. 234. [78] 'Bull. Bot.,' pl. i, figs. 8-12. [79] 'De Anthol.,' p. 37. [80] Moquin, loc. cit., p. 305. [81] 'Neue Denkschr. der Allg. Schweiz. Gesell.,' band v, pl. ii. p. 5. [82] 'Hesperides,' auctore Ferrario. Rome, 1646, fig. 415, pp. 213 and 215. See also Michel, 'Traité du Citronnier.' [83] 'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294. [84] 'Org. Véget.,' vol. ii., p. 41. CHAPTER III. SOLUTION. The isolation or separation of different whorls that are ordinarily adherent together is by no means of rare occurrence. Were it not that the isolation is often congenital, the word detachment would be an expressive one to apply to these cases, but as the change in question occurs quite as often from a want of union, an arrest or stasis of development, as from a _bonâ fide_ separation, the word solution seems to be, on the whole, the best. It corresponds in application to the word _liber_ (_calyx liber_, &c.), in general use by descriptive botanists. As here employed, the term nearly corresponds with the "adesmie hetérologue" of Morren. Moquin Tandon does not make any special subdivision for the class of cases here grouped together, but places them all under "Disjonctions qui isolent les organes." It seems, however, desirable to have a separate word to express the converse condition of adhesion, and for this purpose the term solution, as above stated, is here employed. Diagrammatically, the condition may be expressed by placing a dotted line at the side of the letters thus: : s s s s s : : c c c c c : would indicate the disjunction of the sepals from the carpels (c), in contradistinction to adhesion, which may be represented by the unbroken line thus: | s s s s s | | c c c c c | =Solution of the calyx from the ovary.=--Of all the instances of adhesion which take place under ordinary circumstances, that between the calyx and the ovary is perhaps the most common. The _calyx adhærens_ or _superus_ is a structural characteristic to which all botanists attach considerable importance; so that when exceptional cases occur in which the calyx becomes detached from the ovary, becomes, that is, _inferus_ or _liber_, a proportionate degree of interest attaches to the irregularity. It is not within the scope of the present work to inquire whether this detachment be real or merely apparent, arising from a want of union between parts ordinarily united together. This point must be left to the organogenists to decide in each particular case. So also the question as to what share, if any, the expanded and dilated flower-stalk may take in what are usually called inferior ovaries, can be here only incidentally touched upon. Among _Rosaceæ_, the change in question is very common, especially in conjunction with an elongation of the axis of the flower (apostasis) and with prolification, though it is by no means always co-existent with these malformations. When this alteration in the apparent relative position of calyx and carpels occurs in roses (_Rosa_) the appearances are generally such as to indicate that the "hip" of the rose is a dilatation of the peduncle, continuous above with the coherent bases of the sepals; this inference seems also to be borne out by what happens in the _Pomaceæ_. In some cases in this sub-order, the calyx becomes detached from the carpels, so that the latter organs become more or less "superior," and distinct one from the other. This happens constantly in the double-flowered thorn, _Cratægus Oxyacantha_, in some blossoms of which the hollowed end of the peduncle still invests the base of the carpels, leaving the upper portions detached. In apples flowers are occasionally met with of greater size than usual and on longer stalks, so that the whole looks more like a rose than an apple blossom. In these cases it will usually be found that the calyx consists of distinct sepals, without a trace of the ordinary swelling beneath the flower. The petals are often more numerous than usual; the stamens variously changed, and the carpels sometimes absent; at other times, as in the instance figured in the adjacent woodcuts, figs. 36, 37, consisting of separate, superior ovaries, sometimes destitute of ovules, or, at other times, having two of these bodies.[85] [Illustration: FIG. 35.--Proliferous Rose. Showing an absence of the usual dilatation of the flower-stalk, and other changes.] This condition accords precisely with the account of the development of the flowers in _Pomaceæ_ as given by Payer, Caspary, and others, so that the flowers above described would owe their deficiency of the swollen receptacle to an arrest of development. M. Germain de Saint Pierre, among other malformations of the rose, presented to the Botanical Society of France in 1854[86] two specimens which are of special interest as relating to this contested point. In the one, the swollen portion beneath the flower was surmounted by five perfect leaves, as, indeed, is not infrequent in such malformations; here, then, the calyx could have had little or no share in the production of the swelling in question. In the other, the swollen portion was actually above the insertion of the sepals here represented by five perfect leaves. [Illustration: FIG. 36.--Section through Apple blossom, showing detachment of calyx from ovaries, absence of dilated flower-stalk, &c.] [Illustration: FIG. 37.--Calyx detached from carpels in Apple.] On the other hand, M. Planchon's specimen of the Quince before alluded to, not to mention other instances, tends to show that the bases of the sepals do sometimes enter into the composition of the pome. And, indeed, in many of these cases it would be impossible to say where the axial or receptacular portion ended, and the foliar portion began. As both from normal organogeny as well as from unusual conformation contradictory inferences may be drawn, it would obviously be unsafe to attempt the explanation of the so-called calyx-tube in general from any particular instances; so far as _Rosaceæ_ are concerned, there is so much variation in the relative position of calyx and carpels under ordinary circumstances, that it is no matter for surprise that similar diversities should exist in teratological cases. A similar remark will apply to _Saxifragaceæ_, _Cucurbitaceæ_, _Myrtaceæ_, _Bruniaceæ_, _Rubiaceæ_, and other families of like conformation. [Illustration: FIG. 38.--Flower of _OEnanthe crocata_, in which the five sepals were completely detached from the ovaries, here three in number and destitute of stylopods.] In _Umbelliferæ_, a detachment of the calyx from the ovaries frequently occurs, sometimes without any other change; at other times attended by more serious alterations. So far as can be judged from exceptional occurrences of this kind, it would appear that in this order the axis or flower-stalk does not, in any material degree, enter into the composition of the fruit. In the Rubiaceous genus _Bikkhia_, as mentioned by Duchartre, the ovary is completely inferior, but when the fruit arrives at maturity four small leaves are detached from its surface which had previously adhered to it, and which it seems reasonable to consider as the sepals. In _Campanulaceæ_ a similar separation of calyx from the ovary may be occasionally met with. On the other hand, the occasional formation of a leaf on the inferior ovary of those plants would indicate the axial nature of the fruit. In _Campanumæa_ and _Cyclodon_ the calyx is inferior, while the corolla is superior. In the last-named genus this peculiarity "is carried to the highest degree, the sepals being, in _C. parviflorum_, placed on the peduncle of the flower far removed from the base of the corolla and ovary, whilst in _C. truncatum_ and in _Campanumæa_ they adhere to the base of the tube of the corolla."[87] In this order, then, as in _Saxifragaceæ_, _Bruniaceæ_, &c., no hasty conclusion should be drawn as to the nature of the fruit. In _Brunia microphylla_ the ovary is superior, enclosed within but not adnate to the cup-like calyx, to which latter, however, the petals and stamens are attached. In _Onagraceæ_ (_Jussieua_), as also in _Cactaceæ_ (_Opuntia_), buds have been observed on the surface and edges of the inferior ovary. Indeed, in the former genus, they have been produced artificially, but as buds may be formed on foliar as well as on axial organs, the fact cannot be made great use of in support either of the foliar or axial nature of the inferior ovary. In _Epilobium_, I have met with four perfect leaves at the summit of the ovary, in the place usually occupied by the sepals. This would also favour the notion that the axis entered into the constitution of the fruit in this genus. Mr. B. Clarke, in his 'New Arrangement of Phanerogamous Plants,' p. 4, cites a case wherein the perianth was completely detached from the surface of the ovary in _Cannabis sativa_. It must be borne in mind that some of the recorded instances of change in the relative position of the calyx and pistil ought more properly to be referred to a substitution of carpels for stamens, as in _Begonia_, _Fuchsia_, &c. Among _Cucurbitaceæ_, examples have been recorded, both of the detachment of the calyx from the ovary,[88] and of the partial conversion of some of the anthers of the male flower to carpels. The very singular mode of germination of _Sechium edule_ in which the fruit, instead of rotting, becomes thickened into a kind of rhizome or tuber, is a fact that should not be overlooked in investigating the true nature of the fruit in this order. The following are the genera in which the change has been most frequently observed: *Rosa! *Pyrus! *Cratægus! *Daucus! Pastinaca. Torilis. Apium. OEnanthe! Heracleum, Athamanta. Selinum. Carum. Imperatoria. Rudbeckia! *Campanula! Lonicera! Cucumis! Cannabis. =Solution of the stamens from the petals.=--A separation of the stamens from the petals in flowers, wherein those organs are usually adherent one to the other does not often occur unattended by other changes. It has been observed in _Cobæa scandens_ (Turpin), in _Antirrhinum majus_, and in many double flowers. Partial detachment of the stamens from the styles occurs frequently in semi-double flowers of _Orchis_.[89] FOOTNOTES: [85] 'Gard. Chron.,' 1865, p. 554; 1867, p. 599. [86] 'Bull. Soc. Bot. Fr.' 1854, p. 303. [87] Hook et Thoms, 'Præcurs. ad Flor. Ind.,' Journ. Linn. Soc., vol. ii, 1858, p. 6. [88] Lindley, 'Veget. Kingd.,' p. 315. [89] Masters, 'Journal of Linnean Society,' 1866, vol. viii, p. 207. On the subject of this chapter the reader should also consult Moquin-Tandon, 1. c., p. 298. Engelmann, 'De Antholysi,' p. 37, tab. v. C. Morren, 'Bull. Acad. Belg.,' xix, part 3, p. 318. Cramer, 'Bildungsabweichungen,' p. 64. Fleischer, 'Missbild. Cultur. Pflanzen.' As to the nature of inferior ovaries, see also Payer, 'Bull. Soc. Bot. Fr.' i, 1854, p. 283. Germain de Saint Pierre, _ibid._, p. 302. Caspary, 'Bull. Soc. Bot. Fr.,' t. vi, 1859, p. 235. Schleiden, 'Principles of Botany,' English translation, p. 368. Duchartre, 'Elements de Botanique,' p. 574. Le Maout et Decaisne, 'Traité général de Botanique,' p. 57. Bentham, 'Journ. Linn. Soc.,' vol. x, p. 104 (Structure of _Myrtaceæ_), and other treatises on Organography. PART III. ALTERATIONS OF POSITION. Necessarily connected with changes in the arrangement of organs are similar alterations in their position; so closely, indeed, that but for convenience sake, it would be unnecessary to treat them separately. There are, however, some anomalous developments affecting the relative position of organs that could hardly be treated of under any of the preceding paragraphs. There are, also, certain rare instances where an organ is not so much displaced as misplaced; that is to say, it is developed on or from a portion of the plant, which under usual circumstances does not produce such an organ. In the former instance, the altered position is due to or coexistent with other changes, but in the latter case the new growth may spring from organs otherwise in nowise different from ordinary. The word Displacement is here used to signify the unusual position of an organ; while Heterotaxy may serve to include those cases where a new growth makes its appearance in an unwonted situation, as, for instance, a leaf-bud on a root, &c. Prolification is also included under this heading, the unusual position of the buds in these cases being of graver import than the mere increase in number. Alterations in the position of the sexual organs are spoken of under the head of Heterogamy. CHAPTER I. DISPLACEMENT. Real or apparent displacement of organs from their usual position is an almost necessary consequence of, or is, at least, coexistent with a large number of teratological phenomena. It is obvious that abnormal unions or disunions, suppressions, hypertrophies, &c., are very liable to bring about or to be accompanied with changes in the position, either of the parts directly affected or of adjoining organs. In this place, then, it is merely necessary to allude to some of the more important displacements, and to refer for further details to the sections relating to those irregularities of growth on which the displacement depends. =Displacement of bulbs.=--I owe to the kindness of Mr. James Salter a tulip bulb which had been dug up after flowering, and from the base of which were suspended several small bulbs; and I have since seen another specimen showing the same unusual arrangement. The explanation of these formations seems to be that they correspond to the bulbils ordinarily found in the axils of the scales of the parent organ, and which, in some way or another, have been displaced and thrust into the ground. Professor de Vriese figures something of the same kind in _Ixia carminosa_.[90] Of somewhat different nature to those above described was an anomaly described by M. Gay at a meeting of the Botanical Society of France, April 8th, 1859. The plant affected was _Leucoium æstivum_, and the changes observed were apparently attributable to a simple separation of two leaves that are usually contiguous. "Suppose," says M. Gay in describing this malformation, "the first leaf of the terminal bud separated by a long internode from the other leaves, which remain closely packed; and further, suppose an evident thickening of the upper portion of the lengthened internode, and there will be not only a single bulb, bearing with the leaves of the present year all the remnants of the leaves of the two preceding years, but two bulbs placed one above another, on the same axis, separated by the length of the internode." [Illustration: FIG. 39.--Unusual position of bulbs of tulip; the parent-bulb cut open.] The formation of bulbs in the axils of the leaves, as happens occasionally in tulips, is further alluded to under the head of hypertrophy. =Displacements affecting the inflorescence.=--These are, for the most part, dependent on hypertrophy, elongation, atrophy, spiral torsion, &c., but there are a few instances of a different nature, which may here be alluded to as not being coincident with any of the phenomena just mentioned. Sometimes these deviations from the ordinary position have the more interest as affecting characters used to distinguish genera; thus one of the distinctions between rye-grass (_Lolium_) and wheat (_Triticum_) resides in the relative position of the spikelets and the main stem; in _Triticum_ the spikelets are placed with their backs against the rachis, in _Lolium_ with one edge against it; but in a specimen of rye-grass that has come under my own observation, the arrangement was that of _Triticum_. M. Kirschleger relates having found a specimen of _Leucanthemum pratense_, in which the ligulate female flowers were growing singly in the axils of the upper leaves of the stem.[91] The ordinary capitulum would here seem to have been replaced by a spike or a raceme. A less degree of this change wherein a few flowers may be found, as it were, detached from the ordinary capitulum may often be observed in _Compositæ_, _Dipsacaceæ_, &c. I have also met with specimens of _Lamium album_ in which some of the fascicles or clusters of flowers in place of being placed at the same level on opposite sides of the stem were placed alternately one above another. Caspary[92] mentions a flower of _Aldrovanda vesiculosa_, which was elevated on a stalk that was adherent to the stem for a certain distance, and then separated from it. This flower, with the leaf to which it was axillary, evidently belonged to the whorl beneath, where there was a corresponding deficiency. Another flower of the same plant bore on its pedicel a small leaf, which was doubtless the bract raised above its ordinary position. M. Fournier mentions an instance in _Pelargonium grandiflorum_, where, owing to the lengthening of the axis, the pedicels, instead of being umbellate, had become racemose; and I owe to the kindness of Dr. Sankey a somewhat similar specimen, but in a less perfect condition. Here there was but a single flower, and that rudimentary, placed at the extremity of the axis. There were several bracts beneath this flower disposed spirally in the 1/3 arrangement, all being empty, excepting the terminal one. In like manner, a head of flowers becomes sometimes converted into an umbel. =Displacement of leaves.=--A cohesion of parts will sometimes give rise to an apparent displacement, but the true nature of the malformation can, in general, be readily made out. Steinheil[93] found a specimen of _Salvia Verbenaca_, the leaves of which presented very curious examples of displacement arising from cohesion. Two of these leaves placed at the base of a branch were completely fused in their lower thirds, and divided into two distinct lobes at the upper part; each of these lobes seemed to be as large as the limb of an ordinary leaf. Above these was another very broad one, apparently entire, but evidently produced by a complete cohesion of two. This completely fused leaf alternated in position with the imperfectly fused one below it; the alternation is explained by supposing that the opposite leaves of each pair were directed one towards the other, and became fused, and that thus resulted the displacement. The dislocation of the organs took place in one direction for one pair of leaves, and in another direction for the other pair, hence the alternation. Thus, leaves normally opposite and decussate may, by fusion, become alternate. A similar instance occurred to the writer in _Lysimachia vulgaris_, wherein the changes arising from fusion and suppression of parts, &c., were very considerable; as far as the leaves were concerned they presented the following arrangement in succession from below upwards:--first verticillate, then opposite, then spirally alternate, lastly opposite.[94] The term "diremption" has sometimes been applied to cases where leaves are thus apparently dragged out of position. In _Tradescantia virginica_ I have met with opposite connate leaves; the altered position, however, being due to the union of two stems. [Illustration: FIG. 40.--Large-coloured leaf occupying the position of the inflorescence in _Gesnera_, after Morren.] [Illustration: FIG. 41.--Ordinary arrangement of leaves in fascicles of three in _Pinus pinea_ and unusual arrangement of leaves of same plant in spires.] Twisting of the stem is a frequent cause of the displacement of leaves (see spiral torsion), as also hypertrophy, whether that excess of development take place laterally or lengthwise (see elongation). Atrophy or suppression will also frequently bring about an alteration in the position of leaves; sometimes in such a manner that the place of the suppressed organ is occupied by another one. One of the most curious instances of displacement of leaves arising from suppression is that mentioned by Morren,[95] where, in _Gesnera Geroltiana_, a large leaf apparently occupied the extremity of the axis, a position which, under ordinary circumstances, no leaf could assume. The explanation given by the Belgian professor is, that the axis in this case, instead of throwing off a pair of leaves, one on each side, had from some cause or another produced only one; this one not only being much larger than ordinary, but brightly coloured, thus assuming some of the characteristics as well as the position of the inflorescence. Alterations in the usual arrangement of leaves, however, are not always dependent on or coexistent with other teratological changes, but may simply depend on a natural elongation of the internodes, or on fission or multiplication; for instance, in some conifers, such as the Larch, (_Abies Larix_) or _Pinus pinea_, there may be found at different stages in the growth of the branches leaves in crowded fascicles or tufts; while, when growth is more rapid, the leaves may be disposed in a spiral or alternate manner. In the yew (_Taxus_) the leaves at the ends of the shoots not unfrequently lose their usual distichous arrangement and become arranged in a close spiral manner, the elongation of the shoot being arrested. This appears to be the result of the injury effected by some insect. [Illustration: FIG. 42.--Altered arrangement of leaves of yew, _Taxus baccata_.] So, too, the alteration from verticillate to spiral, or _vice versâ_, may take place without any other notable change.[96] This may frequently be seen in Rhododendrons. =Displacement of the parts of the flower.=--This subject is partly touched on in the chapters on solution, adhesion, and in those on hypertrophy, elongation, prolification, &c., so that in this place it is only requisite to offer a few general remarks, and to refer to other sections for further details. Morren, in referring to displacement of the floral organs, mentions an instance in a _Fuchsia_, wherein the four petals in place of being alternate with the sepals were placed in front of them, owing to the adhesion that had taken place between the petals and the stamens. He speaks of this transposition as metaphery.[97] The same author also gives an account of the displacement of several of the organs of the flower in _Cypripedium insigne_, the displacement being consequent, apparently, on a spiral torsion proceeding from right to left, and involving the complete or partial suppression of several of the organs of the flower. The dislocation of organs in a spiral direction led Morren to apply the term "speiranthie" to similar deviations from the usual construction. Changes of this kind among _Orchidaceæ_ are by no means uncommon; the following may be cited by way of illustration. In a specimen of _Oncidium cucullatum_ furnished me by Mr. Anderson, well known for his success as a cultivator of these plants, there was, associated with a cohesion of one sepal with another, and probably dependent on the same cause, a displacement of the sepals and petals--so that all were dragged out of place. This dislocation may be better appreciated by the accompanying formula than even by the woodcut. Let the usual arrangement be thus represented: S P ST P L S S S standing for sepal, P for petal, L for lip, ST for stamen; then the dislocated form may be represented thus: S P P T S S_S L [Illustration: FIG. 43.--Flower of _Oncidium cucullatum_, showing union of two lower sepals, displacement of column and lip, &c.] In a specimen of _Cypripedium_ also furnished by Mr. Anderson the appearance was as represented in the accompanying figure and diagrams, figs. 44, 45. Referring to the plan of the natural arrangement at fig. 46, it will be seen that an explanation of the peculiar appearance of the flower may be arrived at by supposing a disunion and lateral displacement of the upper segment of the outer perianth together with the complete absence of the lower one. In the second or inner whorl of the perianth the lip is merely a little oblique on one side, but the lateral petals are distorted, displaced, and adherent one to the other and to the column, while the posterior shield-like rudimentary anther is completely wanting. [Illustration: FIG. 44.--Malformed flower of _Cypripedium_.] [Illustration: FIG. 45.--Diagram of malformed _Cypripedium_. _o_, outer segments; _i_, inner segments of perianth; _e_, lip; _s_, stigma; _a_, anther.] [Illustration: FIG. 46--- Diagram showing ordinary arrangement in _Cypripedium_. _o_, outer, _i_, inner segments of perianth; _e_, lip, _a_, anther, _a'_, abortive stamen; _s_, stigma.] [Illustration: FIG. 47.--Plan of flower of _Lycaste Skinneri_ showing displacement of organs.] In a specimen of _Lycaste Skinneri_ similar changes were observed, as shown in the plan, fig. 47. Here the posterior sepal was deficient, the two lateral ones were present, one of them with a long tubular spur, _o o_; of the two lateral petals, _i i_, one was twisted out of place, so as partially to occupy the place of the deficient sepal; the lip was represented by two three-lobed segments, _l_, one above and within the other. The column and ovary of this flower were in their normal condition. Cohesion of two or more segments of the perianth is frequently associated with displacements of this nature: thus, in a flower of _Dendrobium nobile_, a diagram of which is given at fig. 48, the uppermost sepal was coherent with one of the lateral ones, and at the same time diminished in size, and, as it were, dragged out of position. All the other organs of the flower are also more or less displaced, forming a minor degree of the change already alluded to, and which Morren termed speiranthy. The changes will be better appreciated by comparing them with fig. 49, a diagram showing the natural arrangement of parts in this species. [Illustration: FIG. 48.--Plan of malformed flower of _Dendrobium nobile_.] [Illustration: FIG. 49.--Plan of natural arrangement in _Dendrobium nobile_. The x x represent processes of the column, perhaps rudiments of stamens.] Sometimes the displacement seems consequent on hypertrophy of one of the parts of the flower, the disproportionate size of one organ pushing the others out of place. This was the case in a violet, fig. 50, in which one of the sepals _s_ was greatly thickened, and the petals and stamens were displaced in consequence. [Illustration: FIG. 50.--Plan of flower of violet showing displacement of petals, &c. At _b_ was a rudiment of a stamen.] It is curious to observe in many of these cases that the transposed organ not only occupies the place of a suppressed or abortive organ, but frequently assumes its colour, and, to some extent, its function. This has been alluded to in the case of the leaf of _Gesnera_ (see p. 88) and in Orchids this replacement seems to be very common; thus, in addition to the cases before mentioned, in a flower of an Odontoglossum, for which I am indebted to Professor Oliver, the two lateral sepals were united together and occupied the position of the labellum, which was absent. A similar occurrence happens occasionally in _Lycaste Skinneri_, thus recalling the structure of _Masdevallia_, where the labellum is normally very small. The arrangement in Lycaste may thus be symbolised: S P st P + S S ___ [Transcriber's note: The underscores represent a horizontal curly brace in the original.] the + indicating the position of the absent labellum. Cases of this kind are the more interesting from their relation to the fertilization of these flowers by insects; it seems as though, when the labellum, which performs so important an office in attracting and guiding insects, is deficient, its place is supplied by other means. Displacement of the parts of the flower from elongation of the receptacle is a not infrequent teratological occurrence, resulting sometimes in the conversion of the verticillate into the spiral arrangement. Instances of this are cited under Elongation, Prolification, &c. In this place it is merely necessary to refer to a curious circumstance that is met with in some double flowers, owing to this separation of some parts of the flower and the cohesion or adhesion of others. Thus, in some double flowers of _Primula sinensis_ and in the Pea (_Pisum sativum_), I have seen a gradual passage of sepals to petals, so that the calyx and corolla formed one continuous sheet, winding spirally around the central axis of the flower, after the fashion of a spiral tube.[98] =Displacement of the carpels= arises from one or other of the causes above alluded to, and when suppression takes place in this whorl it generally happens that the place of the suppressed organ is occupied by one of the remaining ones, which thus becomes partially dislocated. =Displacement of the placentas and ovules= is a necessary result of many of the changes to which the carpels are subject. The disjunction or dialysis of the carpels, for instance, frequently renders axile placentation marginal. Moreover, it frequently happens, when the carpels become foliaceous and their margins are disconnected, that the ovules, in place of being placed on the suture, or rather on the margins of the altered carpel, are placed on the surface of the expanded carpel. Thus, in some double flowers of _Ranunculus Ficaria_ that came under the writer's notice the carpels were open, _i.e._ disunited at the margins, and each bore two imperfect ovules upon its inner surface a little way above the base, and midway between the edges of the carpel and the midrib, the ovules being partly enclosed within a little depression or pouch, similar to the pit on the petals. On closer examination the ovules were found to spring from the two lateral divisions of the midrib, the vascular cords of which were prolonged under the form of barred or spiral fusiform tubes into the outer coating of the ovule. In this instance, then, the ovules did not originate from the margins of the leaf, nor from a prolonged axis, but they seemed to spring, in the guise of little buds, from the inner surface of the carpellary leaf.[99] The occurrence, also, of different forms of placentation in different flowers on the same plant is no unusual thing in malformed flowers; thus, in double flowers of _Saponaria officinalis_ I have met with sutural, parietal, and free central placentation in the same plant.[100] Professor Babington describes in the 'Gardeners' Chronicle,' 1844, p. 557, a curious flower of _Cerastium_, in which, in addition to other changes, the five carpellary leaves "were partially turned in without touching the placenta, which bears a cluster of ovules, and is perfectly clear of all connection with those partitions" (fig. 51). See also Lindley, 'Veg. Kingdom,' p. 497. [Illustration: FIG. 51.--1. Monstrous flower of a _Cerastium_; sepals and petals leafy. 2. Stamens and pistils separate. 3. Ovary cut open to show the imperfect dissepiments and the attachment of the ovules. 4. A deformed ovule.] M. Baillon[101] records flowers of _Bunias_, some with ovules on the margins of the carpels, others with a central branch bearing the ovules; hence he concludes very justly that no fair inference can be drawn from these facts as to the normal placentation of Cruciferæ. The same excellent observer has recorded the occurrence of free central placentation in malformed flowers of _Trifolium repens_.[102] In malformed flowers of _Digitalis_ the change from axile to parietal placentation may often be seen. Mr. Berkeley describes an instance of this nature where the placentas were strictly parietal, and therefore receded from the distinctive characters of the order, and approximated to those of _Gesneraceæ_. The same author alludes to certain changes in the same flower where two open carpels "were soldered together laterally, as was clear by the rudiments of two styles, the placenta being produced only at the two united edges, the outer margins remaining in the normal condition. This may possibly tend to the explanation of some cases of anomalous placentation, for the only indication of the true nature of the placentation is afforded by the two rudimentary styles, in the absence of which the spongy receptacle of the seeds must have been supposed to spring from the medial nerve." In other cases the placentas were parietal above, but axile at the base of the capsule, a striking instance of the facility with which axile placentation becomes parietal, the change being here effected by the prolongation of the axis, and the formation on it of a second whorl of carpellary leaves. In double flowers of _Primulaceæ_ similar alterations in the placentation may often be observed. I have seen in _Primula sinensis_ sutural, parietal, axile, and free central placentation all on the same plant; nay, even in the same capsule the ovules may be attached in various ways, and transitions from one form of placentation to another are not infrequent. The late Professor E. Forbes describes[103] an instance of true foliar and true axile placentation in the same flower in _Vinca minor_. These and many similar changes, which it is not necessary further to allude to, are not so much to be wondered at when it is borne in mind how slight an alteration suffices to produce a change in the mode of placentation, and how frequent is the production of adventitious buds or of foliar outgrowths, as may be seen in the sections relating to those subjects and to Substitutions. It will be remembered, also, how, in certain natural orders, under ordinary circumstances, considerable diversity in placentation exists, according as the margins of the carpels are merely valvate or are infolded so as to reach the centre. Often this diversity is due merely to the changes that take place during growth; thus, the placentation of _Caryophylleæ_, _Cucurbitaceæ_, _Papaveraceæ_, and many other orders, varies according to the age of the carpel, and if any stasis or arrest of development occurs the placentation becomes altered accordingly. It is not necessary, in this place, to enter into the question whether the placenta is, in all cases whatsoever, a dependence of the axis, as Payer, Schleiden, and others, have maintained, or whether it be foliar in some cases, axial in others. This question must be decided by the organogenists; teratologically, however, there can be no doubt that ovules may be formed from both foliar and axial organs, and, moreover, that, owing to the variability above referred to, both in what are called natural and in what are deemed abnormal conditions, it can rarely happen that any safe inferences as to the normal or typical placentation of any family of plants can be drawn from exceptional or monstrous formations. On the subject of placentation the following authors may be consulted: R. Brown, 'Ann. Nat. Hist.,' 1843, vol. xi, 35. Brongniart, 'Ann. Sc. Nat.,' 1834, sér. 2. i, p. 308. Alph. De Candolle, 'Neue Denkschrift der Allg. Schweizer Gesellsch.,' Band v. 1841, p. 9. Duchartre, 'Ann. Sc. Nat.,' 3rd ser., 1844, vol. ii, p. 290. Ibid., 'Elem. Bot.,' p. 574; 'Rev. Bot.,' 1846-7, p. 213. Babington, 'Gard. Chron.,' 1844, p. 557. Lindley, 'Elements,' p. 89; 'Veg. King.,' pp. 313, 497, &c. Berkeley, 'Gard. Chron.,' 1850, p. 612. Unger, 'Nov. Act. Acad. Nat. Cur.,' 1850; and in Henfrey's, 'Bot. Gazette,' 1851, p. 70. Schleiden, 'Principles,' English edit., p. 385. Payer, 'Elem. Bot.,' pp. 196, 211, 224. Baillon, 'Adansonia.' iii, p. 310. tab. iv. Cramer, 'Bildungsabweichungen,' p. 20, &c. Clos, 'Ann. Sc. Nat.,' 5th ser., iii, 313, as well as any of the general treatises on botany. Reference may also be made to the chapters on Prolification and Substitutions (in the case of the carpels and ovules), and to the authorities therein cited. FOOTNOTES: [90] 'Tijdschr. voor. nat. Gesch.,' viii, 1841. tab. ii, p. 178. [91] Communication to the Internat. Bot. Congress, Paris, 1867. [92] 'Bot. Zeit.,' 1859, p. 117, tab. v. [93] 'Ann. Sc. Nat.,' ser. 2, vol. iv, 1835, p. 143. tab. v. [94] See Kirschleger, 'Flora.' 1844. p. 566 (_Scabiosa_). [95] 'Bull. Acad. Belg.,' t. xvii. part ii, p. 387. [96] 'Clos. Mem. Acad. Toulouse,' 5th ser., t. vi. pp. 51, 70. [97] 'Bull. Acad. Roy. Belg.,' xviii. part ii, p. 505, and vol. xvii, part i, p. 196, and vol. xix. part i. p. 260. [98] See also Schlechtendal, 'Bot. Zeit.,' iv, p. 804. _Primula veris, partibus perigonii spiræ in modum confluentibus._ [99] Seemann's 'Journal of Botany,' vol. v, 1867, p. 158. [100] 'Journ. Linn. Soc.,' i, 1857, p. 161. _c. xylog._ [101] 'Adansonia,' ii, 306. [102] 'Adansonia,' iv, p. 70, t. i. [103] Henfrey's 'Bot. Gazette,' i, 265. CHAPTER II. PROLIFICATION. Moquin-Tandon and other writers have classed the production of buds in unwonted situations under the head of multiplication, but, as the altered arrangement is of graver import than the mere increase in number, it seems preferable to place these cases under this heading rather than under that of alterations of number. The adventitious bud may be a leaf-bud or a flower-bud; it may occupy the centre of a flower, thus terminating the axis, or it may be axillary to some or other of its component parts, or, again, it may be extra-floral. In this last case the prolification is of the inflorescence, and is hardly distinguishable from multiplication or subdivision of the common flower-stalk. In accordance with these differences we have median, axillary, and extra-floral prolification, each admitting of subdivision into a leafy or a floral variety, according to the nature of the adventitious bud. Under the head of each variety certain special peculiarities are noticed, but it may here be advisable to add a few general remarks on the subject. Axillary prolification is a much less frequent malformation than the median form. If only the number of orders and genera be reckoned, the truth of this statement will be scarcely recognised; but if individual cases could be estimated, the difference in frequency between the two would be very much more obvious. This may, perhaps, be explained by the fact that the branch has a greater tendency to grow in length than it has to develop buds from the axils of the leaves. The flower is admitted to be homologous with the branch, and it is also known that, up to a certain time, the branch-bud or leaf-bud and the flower-bud do not essentially differ.[104] At a later stage the difference between the two is manifested, not only in the altered form of the lateral organs in the flower-bud, but in the tendency to an arrest of growth, thus limiting the length of the central axial portion. Now, in prolified flowers the functions and, to a considerable extent, the appearance of a leaf-bud or of a branch are assumed, and with them the tendency to grow in length is developed. Median prolification, therefore, in this sense, is a further step in retrograde metamorphosis than is the axillary form. To grow in length, and to produce axillary buds, are alike attributes of the branch; but the former is much more frequently called into play than the latter; for the same reason, median prolification is more common than the axillary form. This is borne out by the frequency with which apostasis, or the separation of the floral whorls one from another, to a greater degree than usual, is met with in prolified flowers. In both forms the adventitious growth is much more frequently a flower-bud or an inflorescence than a leaf-bud or a branch. This may be due to the position of the flowers on a portion of the stem of the plant especially devoted to the formation of flower-buds, to the more or less complete exclusion of leaf-buds, _i.e._ on the inflorescence. This conjecture is borne out by the comparative rarity with which prolification has been observed in flowers that are solitary in the axils of the ordinary leaves of the plant. If the lists of genera appended hereto be perused, it will be seen that nearly all the cases occur in genera where the inflorescence is distinctly separated from the other branches of the stem. In direct proportion, then, to the degree in which one region of the axis or certain branches of a plant are devoted to the formation of flower-buds to the exclusion of leaf-buds, is the frequency with which those flowers become affected with floral prolification. Flowers produced upon indefinite inflorescences are liable to be affected with either form of prolification more frequently than those borne upon definite inflorescences. Prolification in both varieties is also more frequently met with in branched inflorescences than in those in which the flowers are sessile; but the degree of branching seems less material, inasmuch as this malformation is more commonly recorded as occurring in racemes than in the more branched panicles, &c. From the similar arrest of growth in length, in the case of the flower, to that which occurs in the stem in the case of definite inflorescence, it might have been expected that axillary prolification would be more frequent in plants having a cymose arrangement of their flowers than in those whose inflorescence is indefinite; such, however, is not the case. The reason for this may be sought for in the lengthening of the floral axis, so common in prolified flowers--a condition the reverse of that which happens in the case of definite inflorescence. Median prolification occurs frequently in double flowers; the axillary variety, on the other hand, is most common in flowers whose lateral organs have assumed more or less of the condition of leaves. The other coincident changes are alluded to elsewhere or do not present useful points of comparison, and may therefore be passed over. =Prolification of the inflorescence.=--This consists in the formation of leaf-buds or of an undue number of flower-buds on the inflorescence. It must be distinguished from virescence, or the mere green colour of the floral organs, and from chloranthy, in which all or the greater portion of the parts of the flower are replaced by leaves. Prolification is, in fact, a formation of supernumerary buds, leafy or floral, as the case may be, these buds being sessile or stalked, the ordinary buds being not necessarily changed. Prolification of the inflorescence, like the other varieties, admits of subdivision, not only according to the foliar or floral nature of the bud, but according to its position, terminal or median and lateral. Terminal prolification of the inflorescence, whether leafy or floral, is hardly to be looked upon in the light of a malformation[105] seeing that a similar condition is so commonly met with normally, as in _Epacris_, _Metrosideros_, _Bromelia_, _Eucomis_, &c., wherein the leafy axis projects beyond the inflorescence proper; or as in _Primula imperialis_, in which plant, as also in luxuriant forms of _P. sinensis_, tier after tier of flowers are placed in succession above the primary umbel. Nevertheless, when we meet with such conditions in plants which, under ordinary circumstances, do not manifest them, we must consider them as coming under the domain of teratology. =Median foliar prolification of the inflorescence= is frequently met with in _Coniferæ_, and has of late attracted unwonted attention from the researches of Caspary, Baillon, and others, on the morphology of these plants. The scales and bracts of the cone in these abnormal specimens frequently afford transitional forms of the greatest value in enabling morphologists to comprehend the real nature of the floral structure. It would be irrelevant here to enter into this subject; suffice it merely to say that an examination of very numerous specimens of this kind, in the common larch and in _Cryptomeria Japonica_, has enabled me to verify nearly the whole of Caspary's observations. A similar prolongation of the axis occurred in some of the male catkins of _Castanea vesca_, each of which had a tuft of small leaves at their extremity. In the common marigold and in _Lotus corniculatus_ I have also seen instances of this kind. Kirschleger[106] describes a tuft of leaves as occurring on the apex of the flowering spike after the maturation of the fruit in _Plantago_, and a similar growth frequently takes place in the common wallflower, in _Antirrhinum majus_, &c. In cases where a renewal of growth in the axis of inflorescence has taken place after the ripening of the fruit, the French botanists use the term recrudescence, but the growth in question by no means always occurs after the ripening of the fruit, but frequently before. Professor Braun cites the case of a specimen of _Plantago lanceolata_, in which the spike was surmounted by a tuft of leaves and roots, as well as a still more singular instance in _Eryngium viviparum_, in which not only did particular branches terminate in rosettes of leaves provided with roots, but similar growths proceeded from the heads of flowers themselves. Baron de Mélicoq[107] gives a case in _Primula variabilis_, in which at the top of the flower-stalk, in the centre of six flowers, was placed a complete plant in miniature, having three leaves, from the axil of one of which proceeded a rudimentary flower. Mr. W. B. Jeffries also forwarded me a polyanthus (fig. 52) in which the peduncle was surmounted by a small plant, forming a crown above the ordinary flower-stalk, just as the crown of the pineapple surmounts that fruit. A similar instance was exhibited at the Scientific Committee of the Horticultural Society on July 11th, 1868, by Mr. Wilson Saunders; the species in this case was _P. cortusoides_. To Mr. R. Dean I am indebted for a similar proliferous cyclamen, which seems similar to one mentioned by Schlechtendal.[108] This author alludes to an analogous circumstance in the inflorescence of _Cytisus nigricans_, where, however, the change was not so great as in the preceding cases. The instances just cited all occur in plants having an indefinite form of inflorescence; but the production of a tuft of leaves or of a leafy shoot above or beyond the inflorescence is not confined to plants with this habit of growth, for Jacquin figures and describes an instance of this nature in the cymose flower-stems of a Sempervivum. "_Hi racemi_," says he, "_ultra flores producuntur in ramos, foliosos duo bifidos qui tandem trium unciarum longitudinem adepti fuerunt_."[109] [Illustration: FIG. 52.--Inflorescence of _Polyanthus_, bearing a tuft of leaves at the top of the scape intermixed with the flowers.] =Median floral prolification of the inflorescence=, wherein a new inflorescence projects beyond the primary one, is not uncommon in plants having their flowers arranged in close heads or umbels, as in the common wild celery and other _Umbelliferæ_.[110] I have also met with it in _Trifolium repens_, in the umbellate variety of the common primrose, and in the scarlet geranium. Engelmann cites it in _Triticum repens_, Roëper in _Euphorbia palustris_.[111] =Lateral foliar prolification of the inflorescence= is of more common occurrence than the preceding. I have met with it, amongst other plants, frequently in _Brassica oleracea_, _Pelargonium zonale_, SCABIOSA, BELLIS, and many other composites, also in _Leguminosæ_, e.g. _Lupinus_, _Trifolium_, _Coronilla_, &c. Prof. Oliver forwarded me a specimen of _Euphorbia geniculata_ in which, in addition to other changes, there was a series of stalked buds bearing tufts of green scales, but without any trace of stamens or pistil; these adventitious buds occurred within the ordinary involucre of the plant, between it and the stamens. The pistil was unaffected in some cases, while in some others it was entirely wanting, the gynophore being surmounted by a cup-like involucre, divided into three acutely pointed lobes, each with a midrib; these encircled a series of stalked involucels, as before, and among which were scattered a few stamens, some perfect, others partially frondescent. In a specimen of _Scrophularia nodosa_ examined by me one of the lateral buds on each of the cymes was represented, not by a flower, but by a tuft of leaves, the other buds being unchanged. As the inflorescence was much contracted in size, the appearance of the whole plant was greatly changed. Many of the instances of so-called viviparous plants, _e.g._, _Polygonum viviparum_, may be cited under this head.[112] Many species of _Allium_, _Lilium_, _Saxifraga_, _Begonia_, _Achimenes_, normally produce leaf-buds or bulbs in the inflorescence; so, too, leafy shoots are sometimes found in _Alisma natans_, _Juncus uliginosus_, _Chlorophytum Sternbergianum_, &c. As an accidental occurrence, a similar thing has been noticed in _Lychnis coronaria_, _Phaius grandifolius_, _Oncidium cebolleta_, _Epidendrum elongatum_,[113] &c. &c. Here, too, may be mentioned those cases wherein a leaf-bud is found upon the surface of the so-called inferior ovary; generally a leaf only is found, but a leaf-bud may also originate in this situation, and in either case the inference is that the ovary is, in part at least, made of the dilated and hollowed axis. Leaves may occasionally be found in this way on the so-called calyx-tube or on the inferior ovaries of roses, pears, apples, _Pereskia_, _Cratægus tanacetifolia_, &c. The fruits of _Opuntia Salmania_ and of _O. fragilis_ ('Bull. Soc. Bot. France,' vol. i, p. 306; vol. v, p. 115) have been observed to form small fruit-like branches around their summits. This circumstance is more fully treated of in the succeeding chapter relating to Heterotaxy. =Lateral floral prolification of the inflorescence.=--This, which is termed by Engelmann Ecblastesis foliorum sub floralium,[114] is much the most common of all these deviations, and it is met with in every degree, from the presence of a single supernumerary flower in the axil of a bract to the existence of a small cluster or panicle of such flowers. [Illustration: FIG. 53.--Lateral prolification in inflorescence of _Pelargonium_.] It is common in the _Anemone coronaria_ and _hortensis_, also in the common scarlet _Pelargonium_ (fig. 53). It has been frequently recorded in _Poterium sanguisorba_, and in _Sanguisorba officinalis_, and is especially common in _Umbelliferæ_, _Dipsacaceæ_, and _Compositæ_; a familiar illustration in the latter order is afforded by the hen-and-chicken daisy. In some species of Compositæ, indeed, it is a normal and constant occurrence, while in other cases, such as _Filago germanica_, usually described as proliferous, there is not, strictly speaking, any prolification, for the branching of the stalk takes place below the inflorescence, and the branches originate from the axils of ordinary leaves, not from the floral leaves or bracts. _Convolvulus Sepium_ is very commonly subject to the production of flower-buds from the axils of the floral leaves. The several species of Plantain (_Plantago_) seem very liable to this and similar changes. Schlechtendal[115] gives a summary of the various kinds of malformation affecting the inflorescence in _Plantago_, and divides them into five groups, as follows:--1st, bracteate, wherein the inferior bracts are quite leaf-like, as is frequently seen in _Plantago major_. 2nd, roseate; bracts leafy in tufts or rosettes, without flowers, as in the so-called rose plantain, common in old-fashioned gardens in this country. 3rd, polystachyate; spike-branched, bearing other spikes in the axils of the bracts, as in _P. lanceolata_, _P. maritima_, &c. 4th, proliferous, where the flower-stalk bears a rosette, a spike, or a head with other rosettes. 5th, paniculate, in which the inflorescence has become a much-branched pyramidal panicle, covered with little bracts, and with very rudimentary flowers.[116] The first two groups belong rather to frondescence of the bracts; but with regard to the whole of them it will easily be surmised that intermediate forms occur, linking one group to the other, and defying exact allocation in either. Thus, in the borders of richly cultivated fields in the neighbourhood of London I have frequently gathered specimens of _Plantago major_ with a branched spike provided with large leafy bracts, the branches of the spike being but little less in diameter than the ordinary single spike. These specimens would therefore seem to be intermediate between Schlechtendal's bracteate and polystachyate divisions. Wigand[117] also describes an anomalous specimen of _Plantago major_ similar to those just mentioned, but having small lateral spikes in place of large ones. The instance quoted from Professor Braun would fall under the roseate section, as would also that of Kirschleger, though we are expressly told that the tuft of leaves in this last case was not developed until after the ripening of the seed-vessel. One of the characters of the roseate group, according to Schlechtendal, is the absence of flowers, but most persons who have had the opportunity of watching the growth of the rose plantain must have observed the occasional production of flowers, sometimes stalked, in the axils of the leafy bracts, and at the same time have noticed that the internodes become elongated, so that an approach is made to the ordinary spike-like form of the inflorescence. The proliferous group would include such specimens as that of _P. lanceolata_ mentioned by Dr. Johnston,[118] wherein were several spikes, some sessile, others stalked and pendent, the whole intermixed with leaves and disposed in a rose-like manner. I have myself gathered specimens of this nature, occurring in the same plant, at Shanklin, Isle of Wight (fig. 56). [Illustration: FIG. 54.--_Plantago major_, with panicled inflorescence.] [Illustration: FIG. 55.--Inflorescence of _Plantago major_, with bracts partly replaced by leaves and spike branched.] [Illustration: FIG. 56.--Inflorescence of _Plantago lanceolata_, bearing a tuft of leaves and flowers at the end of the flower-scape.] It is rather singular that each species of _Plantago_ seems to have its own perverse mode of growth; for instance, the bracteate, polystachyate and paniculate forms are almost exclusively confined to _P. major_, the roseate form to _P. media_, the proliferous form to _P. lanceolata_. The instances wherein flower-buds originate from the surface of an inferior ovary, as in those cases where the top of the stem is dilated so as to form part of the fruit, would be properly classed under the head of prolification of the inflorescence. As, however, there is still some difference of opinion as to the correct morphological interpretation to be put on some of these cases, it has been thought better to include them under the head of heterotaxy than of prolification. [Illustration: FIG. 57.--Branched inflorescence of _Reseda luteola_.] Some of the cases of prolification of the inflorescence resulting in a branching of an ordinarily simple inflorescence, as in _Reseda luteola_ (fig. 57), might equally well be placed with fission or multiplication of the axile organs. Branched spikes of this character are not so common among Orchids as might be expected. Professor Reichenbach enumerates a few instances in the Report of the International Botanical Congress of London, 1866, p. 121, and the same author gives an illustration in his 'Orchidographia Europoea,' tab. 150. In Grasses, as indeed in other plants with a spicate inflorescence, this change occurs not unfrequently. The common Ray Grass (_Lolium_) is especially subject to the change in question, and among cultivated cereals, maize and wheat occasionally show this tendency to subdivision. One variety of the latter grain is cultivated in hot countries under the name of Egyptian wheat--_Triticum vulgare_, var. _compositum_. Prolification of the inflorescence has been most frequently observed in the following genera: _Leafy_. _Floral_. Ranunculaceæ Ranunculus. Ranunculus! Anemone. Anemone. Cruciferæ. *Brassica! Caryophyllaceæ. Lychnis! Dianthus! Geraniaceæ. *Pelargonium! *Pelargonium! Leguminosæ. *Trifolium! Trifolium! Lotus! Lotus! Coronilla! Cytisus. Cytisus. Rosaceæ. Poterium. *Pyrus! *Pyrus! *Cratægus! Cratægus! *Rosa. Rosa! Sanguisorba. Philadelphaceæ. Philadelphus. Crassulaceæ. Sempervivum. Echeveria. Crassula. Ficoideæ. ?Tetragonia. Cactaceæ. Opuntia. Opuntia. Pereskia. Saxifragaceæ. Saxifraga! Umbelliferæ. Seseli. *Apium! Cnidium. Chærophyllum. Eryngium. Eryngium. Silaus. Heracleum! Heracleum! Hydrocotyle. Hydrocotyle. Daucus. Carum. Selinum. Angelica! Conium. Astrantia. OEnanthe. OEnanthe. Begoniaceæ. Begonia! Valerianaceæ. Valeriana. Dipsacaceæ. *Scabiosa! *Scabiosa! Knautia! Knautia! Compositæ. *Bellis! Centaurea. Calendula. Calendula. Anthemis. Coreopsis. Apargia. Lampsana. Carlina. Arnoseris. Tragopogon! Tragopogon! Rudbeckia! Senecio! Carlina. Bidens! Pyrethrum. Filago. Hedypnois. Cirsium. Lactuca. Campanulaceæ. Prismatocarpus. Lobeliaceæ. Jasione. Ericaceæ. Azalea! Convolvulaceæ. Convolvulus! Convolvulus! Calystegia! Scrophulariaceæ. Scrophularia! Antirrhinum! Gesneraceæ. Achimenes! Primulaceæ. Primula! Primula! Cyclamen! Cyclamen! Plumbaginaceæ. Armeria. Plantaginaceæ. *Plantago! *Plantago! Polygonaceæ. Polygonum! Euphorbiaceæ. Euphorbia! Urticaceæ. Ficus. Amentaceæ. Corylus! Castanea! Castanea. Coniferæ. *Larix! *Cryptomeria! Taxodium! Pinus. Orchidaceæ. Phaius! Ophrys! Epidendrum! Oncidium! Liliaceæ. *Allium! *Ornithogalum! *Lilium! Amaryllidaceæ. Fourcroya Alismaceæ. Alisma! Palmaceæ. Cocos. Juncaceæ. *Juncus! Restiaceæ. Restio! Restio! Elegia! Elegia! Willdenovia! Willdenovia! Cyperaceæ. Carex. Graminaceæ. Dactylis. *Lolium! Festuca. *Zea! *Triticum! *Hordeum! Secale. Phleum. In addition to the papers already cited the following works may be consulted with reference to prolification of the inflorescence: Moquin-Tandon. 'El. Ter. Veg.,' p. 376. Engelmann, 'De Antholysi,' §§ 85-87. Fleischer, 'Missbild. Versch. Cultur. Pflanz.' For figures of Hen and Chicken Daisy (_Bellis prolifera_). see Lobel, 'Ic.,' 477. Sweert, 'Florileg.,' pl. 98, f. 5. 'Hort. Eystett. Plant. Vern.,' fol. iv, f. i. &c. For similar malformations in marigold (_Calendula_), see Lobel, 'Ic.,' 553. 'Act. Acad. Nat. Cur.,' vol. x, p. 208. Jaeger, 'Missbilld.,' 192-195. 'Hort. Eystett.,' pl. æstiv. fol. iii, f. i. Klinsmann, 'Linnæa,' t. x, p. 607. For monstrous plantains, in addition to previous citations, see Camerarius, 'Epist.,' p. 261, _P. rosea_. Matthioli, 'Krauterb,' 245. Lobel, 'Stirp. Advers. Nov.,' p. 128, _P. major paniculata._ J. Bauhin, 'Hist. Plant.,' i, p. 503 _b_. Ibid., p. 503, _a_, _c_, _P. major rosea_, _bracteata paniculata_, _prolifera_, &c. 'Hort. Eystett.,' pl. æstiv., t. vii, f. 2, _P. rosea_ et _P. bracteata_. Lobel, 'Stirp. Hist.,' p. 162. Dodonæus, 'Pempt.,' 1-4, cap. xxiii, P. major spica multiplex, _i.e._ paniculata. Gerard, 'Herbal.' Clusius, 'Plant. Rar. Hist.,' lib. v, p. 109-10, _Plantago augustifolia Gareti prolifera_. Marchand, 'Adansonia,' iv, p. 156. _Coniferæ._--Richard, 'Mem. Conif.,' tab. xiii, f. 9. A. Braun, 'Das Individ.,' 1853, p. 65. De Cand., 'Organogr.,' tab. xxxvi. Wigand, 'Bot. Untersuch.,' 154. Schlechtendal, 'Bot. Zeit.,' 1859, p. 239. Caspary, 'De Abiet. flor. fem. struct. morphol.' Parlatore, 'Ann. Sc. Nat.,' 1862, vol. xvi, p. 215. Cramer, 'Bildungsabweich.,' p. 4, &c., &c. _Gramineæ._--Bauhin, 'Pinax.,' 21. Morison, 'Hist. Plant.,' t. i. Winckler, 'Ephem. Nat. Cur.,' dec. i, ann. 7, 8, p. 151. Irmisch, 'Flora,' 1858, p. 40, &c. See also under Chloranthy, Viviparous plants, &c. =Prolification of the flower.=--In the preceding sections the formation of adventitious buds of a leafy or floral nature on the inflorescence has been considered. A similar production of buds may take place in the flower itself, either from its centre or from the axil of some of its constituent parts. Prolification of the flower is therefore median or axillary, and the adventitious bud itself may be of a leafy or a floral nature. =Median leafy prolification.=--In this malformation the centre of the flower is occupied by a bud or a branch; the growing point or termination of the axis which ordinarily ceases to grow after the formation of the carpels, takes on new growth. This is well shown in the accompanying illustration (fig. 58), representing the thalamus of a strawberry prolonged beyond the fruits into a small leaf-bearing branch. [Illustration: FIG. 58.--Receptacle of strawberry prolonged into a leafy branch. From the 'American Agriculturist.'] [Illustration: FIG. 59.--Flower of _Verbascum_ with five disunited sepals, five similar green petals, and a prolonged branch in the centre of the flower.] In other cases the carpels are entirely absent and their place is supplied by a leafy shoot as in a species of _Verbascum_, which came under my own observation. In this case the petals were virescent, and the stamens and pistils were entirely absent, hence in truth, the so-called flower more nearly resembled a branch. In a flower of a May Duke cherry, for which I am indebted to Mr. Salter, there was a gradual change from the floral to the foliar condition; thus there were five distinct lanceolate sepals, the arrangement of whose veins betokened that they were leaf-sheaths rather than perfect leaves, ten petals partly foliaceous and sheath-like as to their venation, one of them funnel-shaped, but whether from dilatation or cohesion of the margins could not be determined. The stamens were eight or ten in number, their connectives prolonged into foliaceous or petaloid appendages, so that the filament represented the stalk of the leaf. The pistil was entirely absent and its place was supplied by a branch with numerous perfectly formed stipulate leaves. Some flowers of _Anagallis arvensis_ described by Dr. Marchand[119] are so interesting and show so well the gradual stages by which this malformation is arrived at, that it is desirable to cite the summary of Dr. Marchand's researches as given in the 'Gardeners' Chronicle' by Mr. Berkeley, taking that instance first in which the parts of the flower departed least from the normal condition, and then the others in their proper order. In all the parts there was a greater or less tendency to assume a green tint; in some they were entirely green, in others the brighter colours were confined to the more recently developed parts. "1. In the first case then, the sepals and petals were in their normal position, though rather more dilated than usual; the anthers were fertile, the principal change existing in the ovary, the upper part of which was wanting, so that the ovules were exposed seated on the central placenta. 2. In the next step the calyx, more developed than usual, was separated from the corolla by a long peduncle, and the ovary, which was ovate, contained instead of a placenta a sort of plumule or young shoot. 3. In this case the corolla and calyx were distant from each other; there was no trace of stamens, but the axis was continued from the centre of the corolla, and ended in a leaf-bud. 4. The calyx and corolla nearly as before, but instead of stamens a whorl of little leaves was developed, in the centre of which the axis was continued, bearing at its tip two whorls of leaflets, alternately three and three. 5. In this case two out of the five stamens were normal, the other three changed into leaves, showing clearly the origin of the leaflets, in the last case, which took the place of the stamens. 6. The ovary varied in different flowers. In some the placenta was crowned with ovules; in others the ovules were replaced by a single whorl of leaflets; in others there was every shade of change from ordinary ovules to perfect leaflets; while in others, again, every ovule was converted into a leaf with a long petiole. 7. In these flowers shoots were developed in the axils of the sepals, or on the face of the petals between the point of their insertion and that of the stamens, and, what is most curious, in the interior of the ovaries round the foot of the placenta. 8. Here, again, a very singular condition presented itself: the calyx and corolla separated from each other, the stamens partly developed, the axis continued beyond the corolla, branched and bearing normal leaves so as exactly to resemble an ordinary stem, while in consequence of the calyx and corolla being bent down to the ground, adventitious roots were developed from the axis on the under side above each of them. In another case, where the calyx and corolla were approximated, the ovary was open above, and sent out six shoots from within, perfectly developed, clearly representing the central placenta and five axile buds, and each giving out a number of adventitious roots at its base." In other genera of the same order (_Primulaceæ_) an extension of the placenta into a leafy branch has been observed, as in _Lysimachia_, where in one case the prolonged placenta was removed and struck as a cutting.[120] In _Ericaceæ_ too, the axile placenta has been seen ovuliferous at the base and prolonged above into a leafy branch.[121] =Median floral prolification.=--This is of more frequent occurrence than the preceding. The prolonged axis is more frequently terminated by a flower-bud than by a leaf-bud, though it must be remarked, that the lengthened and protruded stem frequently bears leaves upon its sides, even if it terminate in a flower, and thus the new growth partakes of a mixed leafy and floral nature. Instances of this kind have long been familiar to observers, and have always excited attention from the singularity of their appearance. In one of the old stained-glass windows, apparently of Dutch manufacture, in the Bodleian Picture Gallery at Oxford, is a representation of a _Ranunculus_ affected with median floral prolification.[122] In pinks the affection is not unfrequently met with. Fig. 60 shows an instance of the kind copied from Schotterbec. A singular instance of prolification in the central flower of one of the verticillasters of _Phlomis fruticosa_ fell under my own notice; it was a case wherein the calyx was torn on one side, and one of its lobes had become petaloid. Between the calyx and the corolla were three or four spathulate, hairy, bract-like organs; the corolla and stamens were unchanged; but in place of the usual four-lobed ovary there was a single carpel with a basilar style, terminated by a forked stigma. Occupying the place of the other lobes of the pistil was an oblong woolly flower-bud, consisting of calyx, corolla, and stamens, but with no trace of pistil. I have been unable to find recorded any instance of malformation among Labiates or Borages at all similar to this. It differed from most other examples of prolification in that the axis was not prolonged, the adventitious bud occupying precisely the position of the three lobes of the ovary that were absent. The sole remaining carpel had a style and a stigma as perfect in appearance as though the pistil had been complete. [Illustration: FIG. 60.--Flower of _Dianthus_ affected with median floral prolification.] In a flower of _Conostephium_ (_Epacridaceæ_) forwarded to me by Mr. Bentham, there was a similar adventitious bud placed by the side of the pistil, but as the latter contained the usual number of cells it is probable that the supernumerary bud in this case originated rather from the side than the end of the axis. Certain families of plants present this deviation from their ordinary structure with greater frequency than others: the following orders seem to be the most frequently affected by it: _Ranunculaceæ_, _Caryophyllaceæ_, _Rosaceæ_; while it is commonly met with in _Scrophulariaceæ_, _Primulaceæ_ and _Umbelliferæ_. Of genera which seem peculiarly liable to it may be mentioned the following: _Anemone_, _Ranunculus_, _Cheiranthus_, _Dianthus_, _Dictamnus_, _Daucus_, _Rosa_, _Geum_, _Pyrus_, _Trifolium_, _Antirrhinum_, _Digitalis_, _Primula_. A reference to the subjoined list of genera affected by this malformation, and the knowledge of its comparatively greater frequency in some than in others of them, will show that it is more often met with in plants having an indefinite form of inflorescence than in those having a definite one. The change may affect some only, or the whole of the flowers constituting an inflorescence; and though it is by no means a constant occurrence, it very frequently happens that the central or terminal flower in a definite inflorescence is alone affected, the others remaining in their ordinary condition, as in pinks (_Dianthus_); and in the indefinite forms of inflorescence, it is equally common that the uppermost flower or flowers are the most liable to be thus affected. In those plants which present this deviation from the ordinary condition with the greatest frequency, it often happens that the axis is normally more or less prolonged, either between the various whorls of the flower, as in the case of the gynophore, &c., or into the cavity of the carpels, as in the instances of free central placentation. To bear out this assertion, the following instances taken from those genera having definite inflorescence, and which are very commonly affected with prolification, may be cited; thus, in _Anemone_ and _Ranunculus_ the thalamus is prolonged to bear the numerous carpels; in _Dianthus_ there is a marked internode separating the carpels from the other parts of the flower; in _Primulaceæ_ central prolification is very common, and this is one of the orders where the placenta seems from the researches of Duchartre and others, to be truly a production of the axis within the carpels;[123] in _Thesium_ also, another genus with free central placenta, this malformation has been found. So also among plants with indefinite inflorescence, prolification seems very frequently to affect those wherein the axis is normally prolonged; thus it is common in _Dictamnus_, which plant has an internode supporting the pistil; it is frequent among _Umbelliferæ_, where the carpophore may be truly considered an axile production; it is common among _Rosaceæ_ and _Ranunculaceæ_, in many of which the axis or thalamus is well-marked, and it is by no means infrequent in the flowers of the Orange, where the floral internodes are also slightly elongated; on the other hand, there is no case on record in _Magnoliaceæ_, and some other orders where the floral part of the axis is at some point or other elongated; still, on the whole, there can be but little doubt that there is a real relation between prolification and the normal extension of the floral internodes. Under these circumstances, those instances wherein the parts of the flower become separated one from the other by the elongation of the internodes (apostatis), constitute a lesser degree of the same change, which operates most completely in the formation of a new bud at the extremity of the prolonged axis. Some specimens of _Geum rivale_ (a plant very liable to become prolified) in my possession show this very clearly. In the wild plant the thalamus is elevated on a short stalk; in the abnormal ones the thalamus is simply upon a longer stalk than usual, or in a more advanced stage of the deviation the lengthened thalamus takes the form of a branch provided with leaves and terminated by a flower; it is noticeable, also, in these specimens, that the sepals of the lower flower have assumed entirely the dimensions and appearance of leaves. Median prolification has occasionally been recorded in flowers that have, in their ordinary condition, but one carpel, as in _Leguminosæ_ and in _Santalaceæ_. In _Leguminosæ_, as also in _Amygdalus_, it would seem as if the adventitious bud were strictly a lateral and axillary production, and moreover that the carpel itself is not strictly terminal but lateral in position, though apparently terminal from the abortion of other carpels. In the only recorded instance that I am aware of, of this malformation affecting the genus _Thesium_, the pistil was altogether absent, and occupying its place was the new bud or branch.[124] [Illustration: FIG. 61.--_Daucus Carota_, showing leafly carpels, prolification, &c.] As the carpels are not unfrequently absent in cases of median prolification, it has been thought that the pistil in such cases was metamorphosed into a stem bearing leaves or flowers. Setting aside the physiological difficulties in the way of accepting such an opinion, an examination of any number of cases is sufficient to refute it; for, as Moquin well remarks, the carpels may frequently be found either in an unaltered condition or more or less modified. If the pistil be normally syncarpous, its constituent carpels, if present at all in the prolified flower, become disjoined one from the other to allow of the passage between them of the prolonged axis; thus in some malformed flowers of _Daucus Carota_ gathered in Switzerland (fig. 61), not only was the calyx partially detached from the pistil, but the carpels themselves were leaf-like, disjoined, and unprovided with ovules; between them rose a central prolongation of the axis, which almost immediately divided into two branches, each terminated by a small umbel of perfect flowers, surrounded by minute bracts.[125] Not only are the carpels thus frequently separated one from the other by the prolonged axis, but they undergo commonly a still further change in becoming more or less completely foliaceous, as in the _Daucus_ just mentioned, where the carpels were prolonged into two lance-shaped leaves, whose margins in some cases were slightly incurved at the apex, forcibly calling to mind the long "beaks" that some Umbelliferous genera have terminating their fruits--for instance, _Scandix_. Dr. Norman, in the fourth series of the 'Annales des Sciences,' vol. ix, has described a prolification of the flower of _Anchusa ochroleuca_, in which the pistil consisted of two leaves, situated antero-posteriorly on a long internode, with a small terminal flower-bud between them; and numerous similar instances might be cited. In this place may also be noticed those instances wherein the placenta elongates so much that the pericarp becomes ruptured to allow of the protrusion of the placenta, although this prolongation is not attended by the formation of new buds. Cases of this kind occurring in _Melastoma_ and _Solanum_ have been put on record by M. Alph. de Candolle.[126] This is a change analogous with that which occurs in some species of _Leontice_ or _Caulophyllum_, as commented on by Robert Brown. See 'Miscellaneous Botanical Works' of this author, Ray Society, vol. i, p. 359. If the pistil be apocarpous, and the carpels arranged spirally on an elevated thalamus, it then frequently happens that the carpels, especially the upper ones, become carried up with the prolonged axis, more widely separated one from the other than below, and particularly liable to undergo various petalloid or foliaceous changes as in proliferous _Roses_, _Potentilla_, &c. [Illustration: FIG. 62.--Median floral prolification, &c., in flower of _Delphinium_.] Fig. 62, copied from Cramer, shows an instance of this kind in _Delphinium elatum_, where not only is the thalamus prolonged, and the carpels separated, but from the axils of some of the latter which have assumed from the disunion of their margins somewhat of the appearance of leaves, other flowering branches proceed--axillary prolification. If, on the other hand, the carpels be few in number, and placed in a verticillate manner, the axis then generally passes upwards without any change in the form or position of the carpels being apparent, as in a proliferous columbine, figured in the 'Linnean Transactions,' vol. xxiii, tab. 34, fig. 5. When a flower with the ovary naturally inferior or adherent to the calyx becomes prolified, a change in the relative position of the calyx and ovary almost necessarily takes place, the latter becoming superior or detached from the calyx; this has been already alluded to in _Umbelliferæ_. In a species of _Campanula_ examined by me, the calyx was free, the corolla double, the stamens with petaloid filaments, and in the place of the pistil there was a bud consisting of several series of green bracts, arranged in threes, and enclosing quite in the centre three carpellary leaves detached from one another and the other parts of the flower, and open along their margins, where the ovules were placed. In other similar instances in the same species of _Campanula_, the styles were present, forming below an imperfect tube which surrounded the adventitious bud; in another, contrary to what occurs usually in such cases, the ovary was present in its usual position, but surmounted by a bud of leafy scales, enclosed within the base of a tube formed by the union of the styles. A similar relative change in the position of the calyx and the ovary takes place when the _Compositæ_ are affected with central prolification, or even in that lesser degree of change which merely consists in the separation and disunion of the parts of the flower, but which in these flowers appear to be, as it were, the first stage towards prolification. I owe to the kindness of Professor Oliver a sketch of a species of _Rudbeckia_? showing this detachment of the calyx from the ovary. In a monstrous _Fuchsia_ that I have had the opportunity of recently examining, the calyx was similarly detached from the ovary simultaneously with the extension of the axis. Here the petals were increased in number and variously modified, the stamens also; while in the centre and at the top of the flower, conjoined at the base with some imperfect stamens, was a carpel open along its ovuliferous margins. Such instances as these seem to be the first stages of a change which, carried out more perfectly, would result in the formation of a new bud on the extremity of the prolonged axis. In _Orchidaceæ_, among which family I have now met with several instances of prolification, the ovary seems usually to be absent. Fig. 63 shows a prolified flower of _Orchis pyramidalis_ in which the perianth was nearly regular, the central portions of the flower absent, and their place supplied by a new miniature raceme. This specimen was forwarded to me by Dr. Moore, of Glasnevin. [Illustration: FIG. 63.--Median prolification in _Orchis pyramidalis_, the outer segments of the perianth regular and reflexed.] As might be expected, it very rarely happens that median prolification occurs without some other deviation in one or more parts of the flower being simultaneously manifested. Some of these changes have been already mentioned, but others are commonly met with, as, for instance, the multiplication or doubling, as it is termed, of the petals; others, though less frequent, are of more interest. Fusion of two or more flowers in association with prolification is especially common in cultivated specimens of _Digitalis purpurea_; the uppermost flowers of the raceme become fused together so as to form one large, regular, erect, cup-shaped corolla, to the tube of which the stamens are attached, in greater number than ordinary, and all of equal length; the bracts and sepals are confusedly arranged on the exterior of the flower; while in the centre, in the place usually occupied by the pistil, there rises a conical prolongation of the axis, bearing at its outer or lower portion a number of open carpels, provided, it may be, with styles and ovules; these enclose an inner series of scale-like bracts, from whose axils proceed more or less perfect florets; so that in the most highly developed stage a perfect raceme of flowers may be seen to spring from the centre of a cup-shaped regular flower, whose lobes show its compound character. All intermediate stages of this malformation may be found from cases where there is a simple fusion of two flowers with a second verticil of carpels within the outer, up to such cases as those which have been just mentioned. It is worthy of special remark, that in all these cases the flowers at the uppermost part of the raceme are alone affected, and that, in addition to the prolification, there is fusion of two or more flowers, and regularity in the form of the compound corolla and stamens. The calyx of a prolified flower is either unchanged, or it is modified in harmony with the changes in the central part of the flower. If the ovary be normally superior or free from the calyx, then the latter is comparatively rarely altered; for instance, in proliferous pinks (_Dianthus_) the calyx is seldom affected, except, indeed, in those instances where the floral axis is prolonged, and produces from its side a successive series of sepals, as in what is called the wheat-ear carnation; but though these instances may be, as I believe, an imperfect degree of prolification, they do not affect the general truth of the above opinion, that the calyx, if it be free from the ovary, is but rarely changed in a prolified flower; but that this is not a universal rule is shown by proliferous flowers of _Geum rivale_, where the sepals are usually large and leaf-like, as they likewise are frequently in proliferous roses and pears. [Illustration: FIG. 64.--Proliferous rose. Hip absent, sepals leafy, stamens wanting, axis prolonged bearing supplementary flower, &c. (Bell Salter).] Proliferous roses have a special interest, inasmuch as they show very conclusively that the so-called calyx-tube of these plants is merely a concave and inverted thalamus, which, in prolified specimens, becomes elongated (fig. 64) after the fashion of _Geum rivale_, &c.[127] Occasionally from the middle of the outer surface of the urn-shaped thalamus proceeds a perfect leaf, which could hardly be produced from the united sepals or calyx-tube; a similar occurrence in a pear is figured in Keith's 'Physiological Botany,' plate ix, fig. 12. The change which the calyx undergoes when flowers with an habitually adherent ovary become prolified, and wherein the calyx is disjoined from the ovary, has been before mentioned, but it may also be stated that, under such circumstances, the constituent sepals are frequently separated one from the other, and not rarely assume more or less of the appearance of leaves, as in proliferous flowers of _Umbelliferæ_, _Campanulaceæ_, _Compositæ_, &c. As to the corolla, it was long since noticed that prolification was especially liable to occur in double flowers; indeed, Dr. Hill, who published a treatise on this subject, setting forth the method of artificially producing prolified flowers, deemed the doubling to be an almost necessary precursor of prolification;[128] but, though frequently so, it is not invariably the case that the flower so affected is double--_e.g._ _Geum_. If double, the doubling may arise from actual multiplication of the petals, or from the substitution of petals for stamens and pistils, according to the particular plant affected. Occasionally in prolified flowers the parts of the corolla, like those of the calyx, become foliaceous, and in the case of proliferous pears fleshy and succulent. There is in cultivation a kind of _Cheiranthus_? in which there is a constant repetition of the calyx and corolla, conjoined with an entire absence of the stamens and pistils; a short internode separates each flower from the one above it, and thus frequently ten or a dozen of these imperfect flowers may be seen on the end of a flower-stalk, giving an appearance as if they were strung like beads, at regular intervals, on a common stalk. I have seen a similar instance in a less degree in a species of _Helianthemum_. The stamens are subject to various changes in prolified flowers; they assume, for instance, a leaf-like or petal-like condition, or take on them more or less of a carpellary form, or they may be entirely absent; but none of these changes seem to be at all necessarily connected with the proliferous state of the flower. Of more interest is the alteration in the position of these organs which sometimes necessarily accrues from the elongation of the axis and the disjunction of the calyx; thus, in proliferous roses the stamens become strictly hypogynous, instead of remaining perigynous. In _Umbelliferæ_ the epigynous condition is changed for the perigynous, &c. The condition of the pistillary organs in prolified flowers has already been alluded to. Hitherto those instances have been considered in which either the carpels were absent, or the new bud proceeded from between the carpels. There is also an interesting class of cases where the prolification is strictly intra-carpellary; the axis is so slightly prolonged that it does not protrude beyond the carpels, does not separate them in any way, but is wholly enclosed within their cavity. Doubtless, in many cases, this is merely a less perfect development of that change in which the axis protrudes beyond the carpels. This intra-carpellary prolification occurs most frequently in plants having a free central placenta, though it is not confined to them, as it is recorded among _Boragineæ_. A remarkable instance of this is described by Mr. H. C. Watson in the first volume of Henfrey's 'Botanical Gazette,' p. 88. In this specimen a raceme of small flowers was included within the enlarged pericarp of a species of _Anchusa_. But the most curious instances of this form of prolification are, no doubt, those which are met with among _Primulaceæ_ and other orders with free central placentation. Duchartre, in his memoir on the organogeny of plants with a free central placenta, in the 'Ann. des Sc. Nat.,' 3 sér., 1844, p. 290, among other similar instances, mentions two flowers of _Cortusa Matthioli_, wherein the placenta was ovuliferous at the base; but the upper portion, instead of simply elongating itself into a sterile cone, had produced a little flower with its parts slightly different from those of the normal flowers. M. Alph. de Candolle has likewise described somewhat similar deviations, and one in particular in _Primula Auricula_, where the elongated placenta gave off long and dilated funiculi bearing ovules, while other funiculi were destitute of these bodies, but were much dilated and foliaceous in appearance.[129] In some flowers of _Rhododendron_ I have observed a similar condition of the ovules, which, moreover, in the primary flowers, were attached to the walls of the carpels--parietal placentation. In speaking of these as cases of intra-carpellary prolification, it is, of course, impossible to overlook the fact that they differ in degree only from those cases where the lengthened axis projects beyond the cavity of the carpels; nevertheless they seem to demand special notice, because in these particular plants the placenta or its prolongation appears never to protrude beyond the carpels, or at least very rarely. There are, however, numerous instances of such an extension of the placenta and of prolification occurring among _Primulaceæ_ in conjunction with the more or less complete arrest of growth of the carpels.[130] An instance of this kind has come under my own notice in a monstrosity of the chinese primrose, in which the carpels were reduced to a hardly discernible rim surrounding an umbel of five rays, each terminated by a small normally constituted flower-bud. The ovules of a prolified flower are either unaffected, or they occur in a rudimentary form, or, lastly, they may be present in the guise of small leaves. Under the term prolification of the fruit two or three distinct kinds of malformation appear to have been included. The term seems usually to be applied to those cases where from the centre of one fruit a branch bearing leaves, flowers, or another fruit, is seen to project, as happens occasionally in pears. Now, in many instances, not only the fruit, is repeated, but also the outer portions of the flower, which wither and fall away as the adventitious fruit ripens; so that at length the phenomenon of one fruit projecting from another is produced. It is obvious that this form of prolification in no wise differs from ordinary central prolification. Sometimes some of the whorls of the adventitious flower are suppressed; thus, M. Duchartre describes some orange blossoms as presenting alternating series of stamens and pistils one above another, while the calyces and corollas belonging to each series of stamens and pistils were entirely suppressed.[131] In other cases, doubtless, the carpellary whorl is alone repeated, the other whorls of the adventitious flower being completely absent. Another condition, apparently sometimes mistaken for prolification of the fruit, is that in which the carpellary whorl becomes multiplied; so that there is a second or even a third series within the outer whorl of carpels. If the axis be at all prolonged, then these whorls are separated one from the other, and produce in this way an appearance of prolification. This happens frequently in oranges, as in the variety called Mellarose.[132] Moquin has given an explanation of the St. Valery Apples, wherein the petals are sepaloid, the stamens absent, and where there is a double row of carpels, by supposing these peculiarities to be due to "a prolification combined with penetration and fusion of two or more flowers," but it is surely more reasonable to conceive a second row of carpels placed above the first by the prolongation of the central part of the axis. Supposing this view to be correct, the inner calyx-like whorl might be considered either as a repetition of the calycine whorl, or it might be inferred that the corolla was present in the guise of a second calyx. Moquin-Tandon suggests another explanation--namely, that though the stamens are absent in these curious flowers, at least in their ordinary shape, they are represented by the lower row of carpels, which become, in process of development, fused with the upper or true carpels. If this were so, surely some intermediate conditions between stamen and carpel would occasionally be present; but such does not appear to be the case.[133] In some of the instances of so-called proliferous pears the carpels would seem to be entirely absent, and the dilated portion of the axis to be alone repeated. Thus, the axis dilates to form the lower fruit without any true carpels being produced, but at its summit a whorl of leaves (sepals) is formed; above these another swelling of the axis takes place also without the formation of carpels, and this, it may be, is terminated in its turn by a branch producing leaves. In these cases there is no true prolification, but simply an extension of the axis. That the outer portion (so-called calyx-tube) of these fruits is really an axile product there can now be little doubt; and, as if to show their axile nature, they occasionally produce leaves from their sides, as before mentioned. Moquin, in the tenth volume of the 'Bulletin of the Botanical Society of France,' p. 73, says that when the case is one of prolification the lower fruit is larger and is formed of a fleshy mass; moreover, the line of demarcation between the fruits is more distinct, and there are traces of the seed-bearing cavity in the interior, and of calycine lobes at the top. On the other hand, if the case be one of hypertrophy merely, the lowermost fruit is the smallest, and there is no trace of seed-bearing cavity nor of sepals. See also under Hypertrophy. Some other malformations usually referred to prolification of the fruit seem due to branching of the inflorescence, as in _Plantago_, wheat, maize; or to a simple extension of the axis beyond its ordinary limit, as in some cones of firs, &c. It is obvious that the true fruits in these cases are in no wise affected. From these considerations it would appear better to abandon the use of the expression prolification of the fruit, as unnecessary where it is really applicable, and as delusive in the numerous other cases where it is employed. Median prolification of one or other kind has been met with in the following genera: _Leafy_. _Floral_. Ranunculaceæ. Clematis. Anemone! *Anemone! Ranunculus! *Ranunculus! Delphinium. Caltha. Aquilegia! Cruciferæ. Bunias. *Cheiranthus! Erucago. *Matthiola! Sisymbrium! Brassica! Nasturtium. Hesperis. Sinapis! Diplotaxis. Lunaria. Erysimum. Alyssum. Peltaria. Cardamine! Cleome. Cistaceæ. Helianthemum! Caryophylleæ. Dianthus! *Dianthus! Silene! Lychnis! Violaceæ. Viola! Tiliaceæ. Triumfetta! Geraniaceæ. Geranium! Sapindaceæ. Pavia! Pavia! Malvaceæ. Paritium. Hibiscus! Malpighiaceæ. Byrsonima! Rutaceæ. Genera not specified. *Dictamnus! Resedaceæ. Reseda. Caylussa! Aurantiaceæ. *Citrus! Vitaceæ. Vitis. Vitis. Umbelliferæ. Heracleum. Angelica. Thysselinum. *Athamanta. *Daucus! *Torilis. Rosaceæ. *Rosa! *Rosa! *Geum! *Geum! Agrimonia. Amygdalus. Prunus! Spiræa! Spiræa! Rubus. *Pyrus! *Pyrus! ?Leguminosæ Trifolium! Medicago! Melilotus. Pisum! Cucurbitaceæ. Cucumis. Passifloraceæ. Passiflora. Philadelphaceæ. Philadelphus. Onagraceæ. Epilobium! Epacridaceæ. Epacris! Ericaceæ. *Erica. Rhododendron! Convolvulaceæ. Convolvulus. Gentianaceæ. Gentiana. Gentiana. Apocynaceæ. Vinca. Jasminaceæ. Jasminum! Scrophulariaceæ. Verbascum! Antirrhinum! *Digitalis! *Linaria! Veronica. Orobanchaceæ. Orobanche. Labiatæ. Genera not specified. Stachys. Phlomis! Hydrophyllaceæ. Hydrophyllum. Boraginaceæ. Anchusa. Symphytum. Primulaceæ. *Dodecatheon. *Cortusa. *Anagallis! *Anagallis! *Primula. Dipsacaceæ. Scabiosa. Compositæ. Hieracium! Hieracium! Cirsium. Cirsium. Hypochæris. Calendula! Spilanthes. Carthamus. Coreopsis. Campanulaceæ. Campanula. *Campanula! Polygonaceæ. Genera not specified. Rumex. Santalaceæ. Thesium. Liliaceæ. Genera not specified. Tulipa! Hemerocallis! Asphodelus. Hyacinthus! Iridaceæ. Iris. Amaryllidaceæ. Narcissus! Leucojum. Orchidaceæ. Orchis! Habenaria. Cyperaceæ. Carex. Gramineæ. Phleum. =Axillary prolification= is the term applied to those cases wherein one or more adventitious buds spring from the axils of one or more of the parts of the flower. Engelmann makes use of the word ecblastesis to denote the same condition. Both terms are open to the objection that they do not clearly enable us to distinguish prolification occurring within the flower from a similar state originating outside the flower, within the bracts of the inflorescence. This latter condition, called by Moquin-Tandon lateral prolification (see Prolification of the Inflorescence), is as truly axillary as that to which the name is restricted. In consequence of certain peculiarities in the structure of some flowers, to be hereafter alluded to, it is not in all cases easy to decide whether the new growth springs from the interior of the flower, or from the inflorescence beneath the flower. The accessory bud presents itself as a leaf-bud, a branch, a flower-bud, or a miniature inflorescence; it may be sessile, but is far more frequently stalked, and in more than half the number of cases it is a flower-bud or an inflorescence. There may be one or more of these buds; if two only, then they are usually placed directly opposite one to the other, on the opposite sides of the flower. It will be seen, from the appended list, that the orders and genera in which this description of adventitious growth occurs most frequently are the following:--_Cruciferæ_, especially the genus _Brassica_; _Caryophyllaceæ_, e.g. _Dianthus_; _Resedaceæ_; _Leguminosæ_, e.g. _Melilotus_, _Trifolium_, &c.; _Rosaceæ_, e.g. _Rosa_, _Potentilla_, &c.; _Umbelliferæ_, and _Campanulaceæ_. For the most part, these are groups also peculiarly liable to central prolification. All the parts of the flower may be thus affected; but, as might have been anticipated from the foliaceous nature of the sepals, the new bud usually arises from within the axil of one of those organs. Next in frequency to the calyx, the pistil is subjected to this change--the carpels in such a case being disunited and leaf-like. The petals rank next, and lastly the stamens; these latter, indeed, are usually, but not invariably, absent, the new growth occupying their position. Hence it may well be that when such is the case, there is no real axillary prolification, but rather the substitution of a bud for a stamen. Generally, however, the position of the accessory bud is such that it may properly be referred to the axil of an undeveloped or rudimentary stamen. The largest number of instances of this malformation, not merely generically, but also individually, occurs in plants the members of whose floral whorls are not united one to the other; thus, it is far more common in polypetalous plants than in gamopetalous ones. In the prolified flowers belonging to the latter group, the sepals, if not actually uncombined, are only united for a short distance. The same relationship, but in a much less degree, exists in the case of median prolification, as that aberration is likewise most commonly met with in polypetalous flowers. Another feature of interest is the rarity with which axillary prolification is found in irregular gamopetalous blooms. It may be that the irregular and comparatively excessive growth in some parts of these flowers, as compared with others, may operate in checking any luxuriant tendency in other directions. As in the case of median prolification, plants having an indefinite inflorescence are more liable to be affected with ecblastesis than those having a definite one. The degree of branching of the inflorescence may be noticed, as this deformity is far more common in plants whose peduncles are branched than in those which have either a solitary flower or an unbranched flower-stalk. More than two thirds of the entire number of genera cited as the subjects of this malformation have a branched inflorescence of some form or other; and about two thirds of the cases occur in genera having some form of indefinite inflorescence. If individual instances could be accurately computed, the proportion would be even higher. Fully three fourths of the entire number of genera recorded as occasionally the subjects of this irregularity possess in their usual state some peculiarity of the thalamus; for instance, in about a third of the whole number of genera the thalamus is more or less prolonged between some or other of the floral whorl, e.g. _Caryophyllaceæ_, _Potentilla_, _Anemone_, _Dictamnus_, _Umbelliferæ_, &c. About one fourth of the genera have numerous stamens or numerous carpels, or both, springing naturally from the thalamus. In others (about one sixth) the thalamus is enlarged into a disc, or else presents one or more glandular swellings, _e.g._ _Reseda_, _Nymphæa_, _Cruciferæ_. In the last-named family, as has been already remarked, prolification is very common. It would be interesting to ascertain precisely what part of an inflorescence is most liable to this affection; but as information on this point is but rarely given in the records of these cases, I can only give the results of my own observations, which go to show that, in a many-flowered inflorescence, those flowers at the outside, or at the lower portion, seem to be more frequently the subjects of this change than those situated elsewhere. This may probably be accounted for by the fact that the malformation is met with most generally in plants with an indefinite form of inflorescence, and therefore the lowermost or outermost flowers are most fully nourished; the upper flowers being in a less advanced condition, the change is more likely to be overlooked in them; or it may be that from the unusual luxuriance in the lower flowers, the upper ones may be either present in their ordinary condition, or may be (as indeed frequently happens) stunted in the size and proportion of their several parts. =Axillary foliar prolification of the flower.=--The formation of an adventitious leaf-bud in the axil of any of the parts of the flower is not of such common occurrence as the development of a flower-bud in similar situations, nor is it so frequent as median foliar prolification. I have seen leafy shoots proceeding from the axils of the sepals in the flowers of _Brassica_, and a similar occurrence has been noticed in _Caltha palustris_, _Herreria parviflora_, and other plants. Dr. Marchand's flowers of _Anagallis_, previously referred to at p. 117, showed good illustrations of this occurrence, as also some specimens described by Kirschleger in _A. phoenicea_.[134] Steinheil has figured and described[135] a flower of _Scabiosa_ in which there was an adventitious formation of leafy shoots in the axil of the outer calyx. In some flowers, such as _Convolvulus_, _Anemone_, &c., the exact nature of the sub-floral leaves is uncertain, _i.e._ it is open to doubt whether the organs in question are bracts or leaves pertaining to the inflorescence, or whether they are really parts of the flower. When leafy shoots are formed in the axils of such organs, the adventitious growth may be referred to extra-floral prolification, prolification of the inflorescence that is, or to axillary prolification, according to the view taken of the real nature of the sub-floral leaves. So far as the mere occurrence of prolification is concerned, it is not very material which view be adopted. The same remark applies to cases where leaf-buds occur on the outer surface of inferior ovaries, as in _Rosaceæ_, _Pomaceæ_, _Philadelphus_, or _Tetragonia expansa_, as elsewhere mentioned. It would seem more consistent with the general arrangements of parts, that the adventitious buds should be formed more frequently outside than within the flower proper. Knight[136] figures and describes the occurrence of small tubers or fleshy leaf-buds in the axils of the sepals of a potato, a curious illustration of the real morphological nature of the tuber. =Axillary floral prolification of the flower.=--As already stated, this is of more common occurrence than the formation of a leaf-bud in a similar situation. Any of the parts of the flower may thus subtend a flower-bud, though probably the new buds more frequently originate in the axils of the sepals than in the other whorls. In _Cruciferæ_ the change in question is, relatively speaking, very common. In cauliflowers and broccoli I have frequently met with stalked flowers proceeding from the axils of the sepals, so also in some fuchsias I have seen a ring of stalked flower-buds alternating with the petals, which, together with the stamens and pistil, remained unaffected. The number of parts in the supernumerary structures is generally less than the normal flowers. In Mr. Herbert Spencer's 'Principles of Biology,' part iv, p. 37, are figured and described some monstrous inflorescences in _Angelica_ and other _Umbelliferæ_, from which, amongst other things, the author draws the conclusion that there is no absolute distinction between leaf and branch. Without staying for the moment to discuss this matter, it may here be said that the Umbellifers in question apparently owe their peculiarities rather to axillary prolification within the flower, or to prolification of the inflorescence, than to an actual transformation of a flower or any portion of a flower into an umbellule.[137] In the 'Gardeners' Chronicle,' 1855, p. 551, an instance is figured of the production of a supernumerary flower proceeding from the axil of a stamen in a species of _Nymphæa_ (fig. 65). The ovary in this case was wanting, but in its place was a tuft of small leaves. It is curious that among Dr. Kirk's drawings of east tropical African plants now at Kew, there should be one representing a precisely similar state of things. The species in both instances was _Nymphæa Lotus_, or a cultivated variety of it. M. Wesmael[138] describes a very singular case of what appears to have been referable to axillary prolification in the flowers of _Carex acuta_. The rachillus is described as prolonged through the utricle by the side of the stigmas, bearing on its side a bract, then a secondary utricle, from the axil of which sprung a short stem surmounted by an ovary. Wigand, 'Flora,' 1856, mentions a similar change in _Carex glauca_. In this instance the base of the female inflorescence bore lateral spikes, which projected from the utricles; some of these adventitious spikes were female, others female below and male above, others, again, wholly male. [Illustration: FIG. 65.--Flower of _Nymphæa Lotus_, var., showing axillary floral prolification. The section also shows the tuft of leaves that occupied the place of the ovary.] Various changes in the form and arrangement of the several floral whorls accompany axillary prolification; some of these affect the particular organ or organs implicated, and these only, while in other cases some other parts of the flower likewise undergo modification. The changes most commonly met with are such as may be classed under Goethe's theory of retrograde metamorphosis; for instance, if a supplementary bud be developed in the axil of a sepal, that sepal is likely to be more than ordinarily leaf-like in appearance. The dislocation of the affected sepal from its fellows is a very frequent occurrence; in cases of this kind the detached sepal is placed below the others, thus approximating, in position as well as in function, to the bracts. In some of the instances of proliferous pears, on which I shall have occasion to comment, the sepals are described as sharing in the succulent character of the fruit. The petals, under such circumstances, often exist in the guise of sepals or of small leaves; and instances are recorded wherein the place of the calyx and corolla was supplied by a succession of overlapping green scales, from the axils of which the new buds arose. M. Germain de Saint Pierre records such a case in _Trifolium repens_, wherein the calyx and corolla were replaced by overlapping scales, in the axils of each one of which arose a flower; above there was a row of stamens, and in the centre a pistil in the guise of a trifoliate leaf.[139] Such instances seem to afford an extreme degree of a more common change, viz., the diminished size and contracted appearance of the sepals and petals when affected with axillary prolification. They have also a close relationship to such developments as we see in the wheat-ear carnation, in certain species of the genus _Mæsa_ and others, wherein the calyx is repeated over and again, to the partial or complete suppression of the other parts of the flower. All these cases may be in part explained by the operation of the principle of compensation. So far as the androecium is concerned, the stamens either remain unaltered, or they are present in a more or less petal-like condition; but it far more frequently happens that the stamens are entirely suppressed, the adventitious bud supplying their place; thus was it in the _Dianthus_ represented in the adjoining woodcut, fig. 66, where the stamens were entirely absent, and their places supplied by flower-bearing branches. This _Dianthus_ has the more interest from its similarity to the one described by Goethe, Metam. der Pflanzen, cap. 16, sect. 105; but in that instance median prolification also existed. For my specimens I am indebted to Mr. T. Moore. [Illustration: FIG. 66.--Flower of _Dianthus_ sp., calyx removed; petals turned down so as to show the stalked flower-buds springing from their axils.] The pistil, too, is necessarily subject to very grave alterations when affected with this malformation. It is separated into its constituent carpels; and these assume a leaf-like aspect, and are in the great majority of instances destitute of ovules. Indeed, virescence or chloranthy is very intimately connected with this aberration, as might have been anticipated, for if the parts of the flower assume more or less of the condition of stem-leaves or bracts, it is quite natural to expect that they will partake likewise of the attributes of leaves, even at the expense of their own peculiar functions. It occasionally happens that an adventitious bud arises from the axil of a monocarpellary pistil. This takes place sometimes in _Leguminosæ_, and seems to have been more frequently met with in _Trifolium repens_ than in other plants. The species named is, as is well known, particularly subject to a reversion of the outer whorls of the flower to leaves, and even to a leaf-like condition of the pistil. There are on record instances wherein a leaf-bud has been placed in the axil of a more or less leaf-like carpel; while at other times a second imperfect carpel has been met with in the axil of the first.[140] I have myself seen numerous imperfectly developed cases of this kind. It may be asked whether such cases are not more properly referable to central prolification--whether the axis is not in such flowers terminated by two, rather than by one carpel? It is, however, generally admitted by morphologists that the solitary carpel of _Leguminosæ_ is not terminal, but is the sole existing member of a whorl of carpels, all the other members of which are suppressed as a general rule, though exceptional instances of the presence of two and even of five carpels have been described.[141] Again, the adventitious bud or carpel is placed, not laterally to the primary one, or opposite to it, on the same level, but slightly higher up--in fact, in the axil of the primary carpellary leaf. Griffith figures and describes[142] an instance of the kind in a species of _Melilotus_. The stalk of the ovary is mentioned as having a sheathing base, bearing in its axil a prolongation of the axis of inflorescence, in the form of a short spike with hairy bracts and imperfect flowers, the latter having a well-formed calyx and rudimentary petals and stamens. Griffith infers, from this specimen, that the legume is not to be considered as a terminal leaf. _List of Genera in which Axillary Prolification has been observed._ Order Genus. Leaf-bud Flower-bud or From what organ. or Branch Inflorescence Ranunculaceæ Clematis Flower-bud Sepals. Caltha Ditto Ditto. Aconitum Ditto. Delphinium Ditto Sepals, carpels, &c. Anemone! Ditto Involucre? Nymphæaceæ Nymphæa! Fruit? Nymphæa Flower Petal. Cruciferæ *Brassica! Leaf-bud Flower-bud Sepals and petals. Brassica! Ditto Stamens. Brassica! Ditto Ditto Pistil. Cardamine! Ditto Sepals. Matthiola! Ditto Sepals and petals. Cheiranthus! Ditto Sepals. Erysimum Ditto Sepals and pistils. Lepidium! Ditto Petals and stamens. Arabis Ditto Sepals. Diplotaxis Flower, Pistil, calyx inflorescence and corolla. Capsella Capparidaceæ Cleome Flower-bud Sepals. Resedaceæ *Reseda Ditto Ditto. Caryophyllaceæ Arenaria Branch Ditto. Agrostemma Leaf-bud Ditto. *Lychnis Ditto Stellaria Ditto Silene Ditto *Gypsophila Ditto Ditto Sepals and stamens. *Dianthus! Ditto Ditto Sepals. Dianthus! Ditto Inflorescence Petals and stamens. Cucubalus Sepals Saponaria! Sepals and petals. Malvaceæ Alcea Flower-bud Stamen. Aurantiaceæ Citrus! Ditto Ditto. Rutaceæ Dictamnus! Ditto Pistil leafy. Tropæolaceæ Tropæolum! Ditto Petals. Celastraceæ Celastrus Ditto Sepals. Leguminosæ *Melilotus! Inflorescence Sepals and petals. Medicago Flower-bud Sepals. Coronilla Ditto Ditto. Trifolium! Ditto Second carpel Pistil. axillary to first Melilotus! Ditto Ditto Trifolium! Flower-bud Sepals and petals. Rosaceæ Pyrus! Fruit? Fruit? Cerasus! Flower-bud Petals and stamens. Potentilla! Ditto Leafy carpels. Cratægus! Ditto Petals. *Rosa! Ditto Ditto Sepals, petals, stamens and pistil. Myrtaceæ Lecythis Ditto Fruit? Tetragoniaceæ Tetragonia? Ditto Ditto. Cactaceæ Opuntia! Fruit-like Tufts of spines. branch Pereskia Ditto Sepals? Echinocactus Ditto Ditto. Philadelphaceæ Philadelphus Ditto Sepals. Umbelliferæ *Athamanta Ditto Calyx. *Daucus! Ditto Calyx and pistil. Bupleurum Ditto Calyx and pistil. Torilis Ditto Calyx and pistil. Apium Flower-bud Calyx and pistil. Pastinaca Ditto Ditto ditto. Heracleum! Ditto Ditto ditto. Angelica! Umbel Ditto ditto. Campanulaceæ *Campanula! Branch Sepals. Prismatocarpus Ditto Fruit Sepals, &c. Gentianaceæ Gentiana! Flower-bud Sepals. Convolvulaceæ *Convolvulus! Ditto Outer calyx. Solanaceæ Solanum! Ditto Sepals. Solanum Tubers Sepals and petals. Scrophulariaceæ *Digitalis! Ditto Petals, &c. Veronica Raceme Calyx. Primulaceæ Anagallis! Branch Ditto Petals. Primula Ditto Petals and carpels. Polygonaceæ Rumex Ditto Sepals. Santalaceæ Thesium Leaf-bud In place of stamens and pistils, both absent. Euphorbiaceæ? Euphorbia? Ditto Outer bracts? Orchidaceæ Orchis! Flower-bud Perianth. Amaryllidaceæ Leucoium Ditto Ditto. Iridaceæ Iris Ditto Pistil. Liliaceæ Herreria Ditto Sepals. Hyacinthus Flower and Perianth. raceme Convallaria Flower-bud Ditto. Allium Ditto Ditto. Cyperaceæ Carex Inflorescence Utricle. [Illustration: FIG. 67.--Proliferous Rose. Calyx leafy; petals normal, some reflexed; stamens and pistil absent; in their places a branch with leaves and flowers.] [Illustration: FIG. 68.--Rose exhibiting median, axillary, lateral, floral, and leafy prolification in same flower.] =Complicated prolification.=--From what has been before stated it may be seen that prolification of two or more kinds may coexist in the same flower. Mixed leafy and floral prolification is not unfrequent in proliferous roses, where a shoot is, as it were, prolonged through the centre of the original flower and terminated by a second flower, or even by a cluster, as is well shown in the accompanying figure (fig. 67). Median and axillary prolification, also, not unfrequently coexist in the same flower; thus, in a proliferous rose forwarded to me by Mr. W. Thomson (fig. 68), the following changes were observed:--the swollen portion below the calyx, the "hip," was entirely absent; the sepals were leaf-like in aspect, the petals unaffected; above the petals the axis was prolonged for a short distance and then bore a circlet of miniature, sessile roses, destitute, indeed, of calyx, but provided with numerous petals, stamens, and pistils. Above these lateral flowers, the prolonged axis bore a number of scales in many rows. The scales were in their turn surmounted by a whorl of five perfect leaves, beyond which, again, the axis was prolonged into a leafy shoot terminated by a flower bud, the whole constituting a remarkably complicated admixture of elements belonging to the flower, the bud, the inflorescence, and the leafshoot.[143] Proliferous flowers of Orchids also occasionally present great complexity in the arrangement of their parts. An instance of this kind was described by myself from specimens furnished by Dr. Moore, of Glasnevin, in the 'Journal of the Linnean Society,' vol. ix, p. 349, tabs. x, xi, and from which the following summary is extracted: [Illustration: FIG. 69.--Proliferous Orchis. Diagram showing the arrangement of the several organs in the seven outer circles of the flower. Each whorl is numbered, and the position of the axillary buds shown by the small circles.] The primary flowers were composed of five distinct whorls, and of at least two others less perfectly developed. These primary flowers did not give rise to median formations, but they produced secondary buds in the axils of the segments of the perianth. These latter buds were themselves the subject of tertiary prolification of both kinds, median and axillary. The tertiary median growths, like the primary flower, did not develop median buds, but only lateral ones--quaternary axillary prolification. The accompanying diagrams are intended to show the plan of arrangement in these flowers. Fig. 69 shows the disposition of parts in the primary flower and the situation of the axillary buds. Fig. 70 shows the primary flower without any central prolongation, but giving off axillary buds, two of which are shown in the diagram, 2, 2; these are, each of them, the subject of both median, 3, 3, and axillary prolification, 4', 4'. [Illustration: FIG. 70.--Diagram to explain the construction of the double-flowered _Orchis_. 1. The primary flower, with no median bud, the position of which, had it been present, is shown by the dotted line. 2. Two axillary buds proceeding from 1, and themselves giving origin to 3, 3. Median buds, and 3', 3', axillary buds. 4' 4'. Axillary buds, proceeding from 3. No median bud is produced from 3; its situation, had it been present, is indicated by the dotted line.] In _Narcissus major_ a similar combination of both forms of prolification exists, as described by Morren.[144] On the general subject of Prolification in flowers, in addition to the authorities already cited, the reader may refer to the following among many others: Linnæus, 'Prolepsis,' §§ vi et vii. Goethe, 'Versuch. Metamorph.,' cap. xv and xvi §§ 103-106. Moquin-Tandon,' El. Ter. Veg.,' p. 362, &c. Engelmann, 'De Antholys.,' §§ 52-62, &c. Cramer, 'Bildungsabweichungen,' &c. _Orchidaceæ_, _Umbelliferæ_, _Compositæ_, _Leguminosæ_, _Primulaceæ_, _Ranunculaceæ_. Fleischer, 'Missbild. Cultur Gewachs.' Schlechtendal, 'Linnæa,' xv, p. 408, _Rosa_. 'Bot. Zeit.' vol. xx, 1862, p. 382, _Cyclamen_. 'Bot. Zeit.,' vol. xx, p. 301, _Asphodelus_; et _Lilium_. Seringe, 'Bull. Bot.,' i, t. xi, f. 7, 8, _Arabis_, _Diplotaxis_. Clos, 'Mem. Acad. Toulouse,' 5th sér., 1862, _Papaver_. Wigand, 'Flora,' 1856, p. 716, _Hypochæris_; et 'Bot. Untersuch.,' p. 19. Buchenau,' Flora,' 1857, p. 295, _Reseda_. Roeper, 'Bot. Zeit.,' 1852, p. 427, _Orchis_. Presl., 'Linnæa,' vi, p. 599, tab. ix, figs. 5-8, _Sisymbrium_, Vrolik., 'Flora,' 1846, p. 97, t. i et ii, id. 1844, t. i, _Digitalis_. See also Schlechtendal, 'Bot. Zeit.,' vol. ix, 1851, p. 579. Klinsmann, 'Linnæa,' x, p. 604, t. v, _Hesperis_. Fuckel, 'Flora,' 1848, p. 609. _Melilotus_. De Candolle, 'Organogr.,' i, 396, t. 33. Turpin, 'Atlas de Goethe,' p. 65, t. 5, figs. 12, 13. Fenzl. 'Sitzungsbericht d. k. Akad. d. Wissensch. Wien.,' heft, iii, tabs. 3, 4, _Rosa_. Kirschleger, 'Flora,' 1845, 613, _Dianthus_, _Rosa_. 'Institut.,' 1841, No. 413, p. 421, _Tragopogon_. Baron de Melicoq., 'Ann. Sc. Nat.,' 3rd ser., vol. v. 1846, p. 61, _Antirrhinum_. Reichenbach, 'Icon. Fl. Germ.,' tab. 100, _Reseda_--"monstrosa anticipatio Euphorbiacearum et Capparidearum." Duhamel, 'Phys. Arbres.,' liv. iii, cap. 3, p. 303, pl. xii, f. 306, _Rosa_. Caspary, 'Bull. Soc. Bot. Fr.,' vol. vi, 1859, p. 235, Rev. Bibl., _Pyrus_. Eichler, 'Flora,' 1865, tab. ix, _Cleome_. Lindley, 'Elements of Botany,' p. 63, &c., _Rosa_, _Epacris_, _Anagallis_, _Pyrus_. Irmish, 'Flora,' 1858, p. 38, _Pyrus_; and 'Bot. Zeit.,' xix, 1861, p. 342, _Hyacinthus_. Duchartre, 'Bull. Soc. Bot. France,' 1861, p. 451, _Rosa_. Weber, 'Verhandl. Nat. Hist. Verein. Rhein. Preuss., &c.' 1858 et 1860. Landrin, 'Mem. Soc. Sc. Nat. Seine et Oise,' 1866?[145] Masters, 'Trans. Linn. Soc.,' vol. xxiii, p. 359, tab. 34 and p. 481, tab. 54. =Prolification of the embryo.=--This term was applied by Moquin-Tandon to a peculiar condition of the almond (_Amygdalus_), in which, indeed, it is not of unfrequent occurrence. In these cases one almond encloses within its cotyledons a second embryo, and this, again, in some instances, a third, the little plants being thus packed like so many boxes one within the other. The supplementary embryos are, in the ripe state at least, quite separate and detached one from another. These cases differ from the ordinary instances wherein there is an increased number of embryos in one seed in their position. In the latter case, as often happens in the seeds of the orange, the new products are placed by the side one of another.[146] For other cases of prolification or the adventitious formation of buds on leaves, roots, &c., see under Heterotaxy. FOOTNOTES: [104] Linn., 'Prolepsis,' § vii; Goethe, 'Metamorph.,' §§ 96, 103, 106. [105] "Diaphysis inflorescentiarum." Engelmann, 'De Anthol.,' § 85. [106] 'Flora,' 1844, p. 565. [107] 'Ann. Sc. Nat.,' ser. 3, vol. v, 1846, p. 64. [108] 'Bot Zeit.,' vol. xx, p. 382. [109] 'Miscel. Austriac. Bot.,' vol. i, Vindob, 1778, p. 133. [110] "_Umbellati dum prolificantur, augent umbellulam, ut ex umbellula simplici altera exeat_." 'Linn. Phil. Bot.,' § 124. [111] 'En. Euphorb.,' p. 36. [112] Meisner. 'Mon. Gen. _Polygoni_ Prodrom.,' p. 20, tab. v, considers the bulbils of this plant to be modifications of the pedicels of the flower. [113] See A. Braun. 'Ann. Scienc. Nat.,' 4th series, 1860, vol. xiv, p. 13. [114] "_Prolificatio e latere ex calyci communi proles plurimos pedunculatos emittens, fit in compositis aggregatis proprie dictis._" 'Linn. Phil. Bot.,' § 124. [115] 'Bot. Zeit.,' 1857, p. 873. See also 'Verhandl. Nat. Hist. Vereins. Preuss. Rheinl. u. Westphal.,' 1854, t. ix. [116] "Pannicula spicatim sparsa onusta innumera foetura herbaceorum flosculorum racematim cohærentium," 'Lobel. Stirp. Hist.,' p. 163. This is the "Besome Plantain, or Plantain with spoky tufts," of Ray, 'Synopsis,' p. 314. Gerard's 'Herbal,' Ed. Johnson, p. 420. Parkinson, 'Theat. Bot.,' p. 494. Baxter, 'Loudon. Mag. Nat. Hist.,' vol. ix. p. 204, and vol. iii, p. 482. fig. 118. [117] 'Flora.' 1856. p. 706. [118] 'Flora of Berwick-on-Tweed,' vol. i. p. 38. [119] 'Adansonia,' vol. iv. 1864, p. 150, tab. vii. 'Gard. Chron.,' November 19th, 1864. [120] 'Ann. Sc. Nat.,' ser. 3, tom. ii, p. 290; and 'Adansonia,' iii, tab. iv; see also Bureau, in 'Bull. Soc. Bot. France,' x, p. 191. [121] Baillon, 'Adansonia,' i, 286. [122] See also figure in 'Hort. Eystett. Ic. Plant. Vern.,' fol. 15, fig. 1. _Ranunculus asiaticus_. [123] Duchartre, 'Ann. des sc. nat.,' 3me série, vol. ii, 1844, p. 293. [124] Reissek, 'Linnæa,' vol. xvii, 1843, p. 641, tab. xix. [125] The tube of the calyx in these specimens was traversed by ten ribs, apparently corresponding to the primary ridges of the normal fruit; these ribs were destitute of spines, and the bristly secondary ridges were entirely absent. Those portions of the carpels which were detached from the calyx had each three ribs, a central and two lateral ones, which appeared to be continuous with the ribs of the calyx below,--although in the case of the calyx there were ten, in the case of the carpels six ribs, three to each. This diversity in number is thus explained:--A circle of vascular tissue ran round the interior of the calyx-tube, at its junction with the limb, and at the point of insertion of the petals and stamens. The vascular circle seemed to be formed from the confluence of the ten ribs from below. Of the five ribs in each half of the calyx, the three central ones were joined together just at the point of confluence with the vascular circle, above which they formed but a single rib--that traversing the centre of the carpellary leaf; the two lateral ribs of each half of the calyx seemed to be continuous, above the vascular rim, with the lateral ribs of the carpel; these lateral ribs were connected on either side with the central one by short branches of communication. The disposition of the ten ribs may be thus represented:-- 1 1 1 1 1 1 3 2 3 2 3 3 2 3 2 3 1 1 1 1 1 1 1 1 1 1 The lower line of figures represents the calycine ribs, the middle row shows how each of these ribs is divided at the vascular rim, and the uppermost row shows their distribution above the rim. From this it will be seen that six of the calycine ribs divide into three branches, one prolonged upwards as a lateral or median rib into the carpellary leaf, the other running horizontally to join with similar branches sent out from the neighbouring rib; the four intermediate calycine ribs divide into two branches only, which join the side branches of the first mentioned, but have no direct upward prolongation into the carpel. The ten ridges are placed opposite to the sepals and petals. [126] 'Neue Denkschriften der allgemeine Schweizerischen Gesellschaft,' band 5. 1841. tab. 2. [127] Bell Salter, 'Gard. Chron.,' March 13th, 1847, and 'Ann. Nat. Hist.,' 1847, vol. xix, p. 471. &c. [128] 'The Origin and Production of Proliferous Flowers, with the Culture at large for raising Double Flowers from Single, and Proliferous from the Double.' By J. Hill, M.D. London, 1759. [129] A. de Candolle, 'Neue Denkschriften,' op. cit., p. 9; also Unger as cited in 'Botanical Gazette,' May, 1351. p. 70. [130] Duchartre, op. cit. [131] 'Ann. Sc. Nat.,' 1844, vol. i, p. 297. [132] Maout, 'Leçons Elémentaires de Botanique,' vol. ii. p. 488; Ferrari. 'Hesperides.' pls. 271, 315, 405. [133] Moquin-Tandon, loc. cit., p. 386, &c.; see also Trécul, in the 'Bull. Soc. Bot. France,' tom. i, p, 307. [134] 'Bull. Soc. Bot. Fr.,' 1863, vol. x, p. 461. [135] 'Ann. Sc. Nat.,' 1835, p. 65. See also Le Maout, 'Leçons Element.,' vol. ii, p. 426. [136] 'Proc. Hort. Soc.,' vol. i, p. 39, fig. 2. [137] See also 'Nat. Hist. Review,' 1865, p. 377. [138] 'Acad. Roy. Belg.,' April 11th. 1863. [139] 'Bull. Soc. Bot. Fr.,' tom. iii, 1856, p. 479. [140] 'Linnæa,' vol. xv, p. 266, _c. ic._ Caspary, 'Schriften d. Physik.-Oek. Gesell. zu Königsberg,' bd. ii, p. 5, tab. iii, fig. 39, &c. [141] Lindley, 'Veg. King.,' p. 545; also Clarke on the Position of Carpels, Linn. Soc.,' December, 1850. 'Proc. Linn. Soc.,' ii, p. 105. [142] 'Notulæ,' vol. i, Dicot. p. 127. 'Atlas,' pl. xliii. [143] Moquin-Tandon gives the following references to cases of proliferous roses, but some I have not been able to verify. 'Journ. des Sav.,' 22 Mai 1679. Hottinger, 'Ephem. Nat. Cur.,' dec. 3 ann. 9 et 10, p. 249. Marchant, 'Mem. Acad. Scienc. Paris.' 1707, p. 488. Preussius, 'Ephem. Nat. Cur.,' cent. 7 et 8. App. p. 83. Schuster, 'Act. Acad. Nat. Cur.,' vol. vi, p. 185. Spadoni, 'Mem. Soc. Ital.,' t. v, p. 488. See also at the end of this section for numerous other references. [144] 'Bull. Acad. Belg.,' t. xx, part ii, p. 271. See also Bellynck, 'Bull. Soc. Bot. Belg.,' t. vi, ex. 'Bull. Soc. Bot. France,' t. xiv, 1867, Rev. Bibl., p. 241. _Orchis ustulata_. [145] I have not been able to meet with this, but it is said to contain a paper on prolification, with numerous bibliographical references. [146] 'El. Ter. Veg.,' p. 364, Adnot. CHAPTER III. HETEROTAXY. Under this category are here included a variety of deviations from the ordinary arrangement and position of parts which cannot conveniently be classed under the preceding or under other headings. The term heterotaxy is intended to apply to the production of organs in situations where, under usual circumstances, they would not be formed. It thus does not include cases of substitution, where one part is replaced by another, or more or less metamorphosed, nor cases of multiplication, nor of prolification which are characterised not only by the production of members in unwonted situations, but also in unwonted numbers. From the very nature of the anomalies, and specially from the scanty knowledge we possess concerning their mode of development, it is not possible to allocate them in all cases correctly, and moreover many of them might as well be placed in one group as in another. =Formation of adventitious roots.=--This is of exceedingly common occurrence in a vast number of plants, so much so that in most cases it cannot be considered as in any way abnormal; there are, however, a few instances where the formation of these organs may be considered to come within the scope of teratology, or, at least, where their production is the result of injury or of some unfavorable condition to which the plant is exposed. Thus the production of adventitious roots on the stem of the vine is considered to be due to untoward circumstances impairing the proper action of the ordinary subterranean roots. So, too, the formation of roots on the upper portions of stems that are more or less decayed below, as in old willows, is to be considered as an attempt to obtain fresh supplies through a more vigorous and healthy channel. A similar occurrence often arises as a consequence of some injury. Virgil had this circumstance in view when he wrote "_Quin et, caudicibus sectis, mirabile dictu, Truditur e sicco radix oleagina ligno._"--'Georg.' Bk. ii. I have seen many specimens of adventitious roots produced on the olive in the way just mentioned. In the 'Gardeners' Chronicle,' January 8th, 1853, p. 21, is described a curious formation of roots in the fissure between two divisions of a laburnum stem. In the same journal, January 1st, 1853, p. 4, Mr. Booth mentions the case of a Cornish elm, the trunk of which was divided at the top into two main divisions, and from the force of the wind or from some other cause the stem was split down for several feet below the fork. Around the edges of the fracture, layers of new bark were formed, from which numerous roots issued, some measuring an inch in diameter and descending into the cleft portion of the tree: similar instances must be familiar to all observers. It may happen that these roots sent down into the cavity of a decaying trunk may, after a time, become completely concealed within it, by the gradual formation and extension of new wood over the orifice of the cavity formed by the death and decay of the old wood. Such is presumed to be the explanation of a specimen of this kind in the possession of the writer, and taken from a cavity in an apparently solid block of rosewood; externally there were no marks to indicate the existence of a central space, but when the block was sawn up for the use of the cabinet-maker, this root-like structure was found in the centre and attached to one end of the cavity. The production of roots which ultimately serve as props to support the branches, or as buttresses to compensate for the increasing weight of branches and foliage, is also a familiar occurrence. The huge gnaurs and burrs met with occasionally on some trees often produce great quantities, not only of adventitious buds, but of roots also. [Illustration: FIG. 71.--Production of adventitious roots from leaf stalk of celery.] The leaves, equally with the stems, have the power of emitting roots under certain conditions, as when the leaves are in close contact with moist soil or as the result of injury. This happens in some plants more readily than in others--_Bryophyllum calycinum_ is a well-known instance. Mr. Berkeley has described the formation of roots from the fractured leaves of celery,[147] and also in a cabbage where a snail "having gnawed a hole into the middle of a leaf at its junction with the stem, a fascicle of roots was formed, bursting through the tissue lining the cavity, and covered with abundant delicate hairs after the fashion of ordinary radicles." [Illustration: FIG. 72.--Germinating plant of mango, showing production of roots from one of the cotyledons (from the Kew Museum).] The production of adventitious roots is not limited to the ordinary leaves of the plant, but may be manifested on the cotyledons; thus Irmisch describes cases of this kind in the cotyledons of _Bunium creticum_ and _Carum Bulbocastanum_.[148] I have figured and described an analogous case in the cotyledons of the Mango (fig. 72).[149] To this formation of adventitious roots the gardener owes the power he has of propagating plants by cuttings, _i.e._, small portions of the stem with a bud or buds attached, or in some cases from portions of the leaves, of the roots themselves, or even of the fruit, as in the case of the cactus (Baillon). Care also has to be exercised in grafting certain fruit trees not to allow the grafted portion to be too close to the ground, else the scion throws out roots into the soil, and the object of the cultivator is defeated. [Illustration: FIGS. 73 and 74 show formation of roots from leaves induced by the art of the gardener.] Layering is another garden operation dependent on the formation of these organs, and advantage is also sometimes taken of this tendency of some plants to produce roots when injured to reduce the dimensions of a plant when getting too large for the house in which it is growing. By gradually inducing the production of new roots from the central or upper portions of the stem, it becomes possible, after a time, to sever the connection between the original roots and the upper portion of the trunk, and thus secure a shortened plant. On the subject of adventitious roots, &c., reference may be made to Trécul, 'Ann. Sc. Nat.,' 1846, t. v, p. 340, et vi, p. 303. Duchartre, 'Elements de Botanique,' p. 219. Lindley, 'Theory and Practice of Horticulture.' Thomson's 'Gardener's Assistant,' pp. 374, _et seq._; and any of the ordinary botanical text-books. =Formation of adventitious buds on roots.=--One of the characteristics by which roots are distinguished from stems in a general way consists in the absence of buds; but, as is well known, they may be formed on the roots under certain circumstances, and in certain plants, e.g., _Pyrus Japonica_, _Anemone Japonica_, &c. What are termed suckers, owe their origin to buds formed in this situation. If roots be exposed or injured, they will frequently emit buds. The well-known experiment of Duhamel, in which a willow was placed with the branches in the soil and the roots in the air, and emitted new buds from the latter and new roots from the former, depended on this production of adventitious organs of either kind. Gardeners often avail themselves of the power that the roots have of producing buds to propagate plants by cuttings of the roots, but in many of these cases the organ "parted" or cut is really an underground stem and not a true root. M. Claas Mulder has figured and described a case in the turnip-radish of the unusual formation of a leafy shoot from the root, apparently after injury.[150] From the figure it appears as if the lower portion of the root had been split almost to the extremity, while the upper portion seems to have a central cavity passing through it. From the angle, formed by the split segments below, proceeds a tuft of leaves, some of which appear to have traversed the central cavity and to have emerged from the summit, mingling with the other leaves in that situation. The production of a flower-bud has even been noticed on the root of a species of _Impatiens_. =Formation of shoots beneath the cotyledons.=--The tigellar or axial portion of the embryo plant, as contrasted with the radicle proper, is very variously developed in different cases; sometimes it is a mere "collar" bearing the cotyledons, while at other times it is of considerable size. Generally it does not give origin to shoots or leaves other than the seed-leaves, but occasionally shoots may be seen projecting from it below the level of the cotyledons. This happens frequently in seedling plants of _Anagallis arvensis_, _Euphorbia_ _peplus_, and other species, _Linaria vulgaris_, some _Umbelliferæ_, &c.[151] =Adventitious formation of leaves.=--The term phyllomania has been vaguely applied both to the production of an unwonted number of leaves and to their development in unusual situations. Under the present heading the latter class of cases are alone included. The extraordinary tendency in some Begonias to develop leaves or leafy excrescences from their surfaces is elsewhere alluded to, and is, in reality, a species of hypertrophy or over-luxuriant growth. In some flowers where the inferior ovary is supposed to be, in part at least, formed by a dilatation of the top of the flower-stalk, leaves have been met with proceeding from the surface of the ovary or fruit, as in _Cratægus tanacetifolia_, roses, pears, gooseberries, &c. In a specimen of _Nymphæa alba_ I have met with scale-like leaves projecting from the surface of the fruit (or torus?), and which did not appear to be metamorphosed stamens or styles (fig. 76). [Illustration: FIG. 75.--Leaf proceeding from hip of the Rose.] [Illustration: FIG. 76.--Leaves proceeding from the ovary of _Nymphæa_.] For other illustrations of increased leaf-formation, see Multiplication of foliar organs. [Illustration: FIG. 77.--_Leontodon_. Scape with two leaves; the bracts of the involucre are also leafy.] =Production of leaves on a usually leafless inflorescence.=--The development of the bracts of an inflorescence to such an extent that they resemble ordinary leaves is elsewhere alluded to as of common occurrence. It happens far less frequently that leaves are developed on an inflorescence usually destitute of them, without any metamorphosis or substitution, and without any formation of adventitious buds, such as happens in prolification. Such a partial change from a floriferous to a foliiferous branch may be seen in a specimen of _Sambucus nigra_ in the Smithian herbarium in the Linnean Society, where the ultimate branches of the cyme bear small leaves. My attention was directed to this specimen by the Rev. W. Newbould. Jacquin figures an analogous case in _Sempervivum sediforme_,[152] in which the branches of the inflorescence were prolonged into leafy shoots. Sometimes from the side of a flower-stalk or scape, which usually does not bear leaves, those organs are produced. The common dandelion, _Taraxacum_, sometimes offers an illustration of this, and also the daisy (_Bellis_).[153] In a specimen of fasciated cowslip given me by Mr. Edgeworth there was a similar formation of leaves on the flattened stalk. =Production of leaves or scales in place of flower-buds.=--The position of the leaf and of the flower-buds respectively is, in most plants, well defined, but occasionally it happens that the former is formed where, under ordinary circumstances, the latter organ should be. This may happen without the formation of any transitional organs between the two, and without actual increase in the number of the buds. Where there is evidently a passage from leaf-bud to flower-bud, or _vice versâ_, the case would be one of metamorphy. If the number of buds be augmented, or they be mixed with the flower-buds, then it would be referable to leafy prolification of the inflorescence. There remains a class of cases wherein there is a complete substitution of one structure for the other, it may be without the slightest indication of transition between the two, and without any admixture of leaf-buds among flower-buds, or any absolute increase in the number of organs, as in Prolification. Such a case is represented in fig. 78, which shows a portion of the stem of a species of _Valeriana_, bearing at the summit, not an inflorescence, but a tuft of leaves without the slightest indication of flowers. Drs. Hooker and Thomson relate that in Northern India the flowers of _Anemone rivularis_ are very generally absent, and their place supplied by tufts or umbels of leaves.[154] In the collection of the late Mr. N. B. Ward was a specimen of lupin in which the flowers were all absent, and their place supplied by tufts of leaves. [Illustration: FIG. 78.--Tuft of leaves replacing the inflorescence in a species of _Valeriana_.] A similar appearance has been noticed in _Compositæ_, and I owe to the kindness of Professor Oliver the communication of a specimen of a species of _Bidens_ from Peru, in which the capitula, instead of consisting of florets, as usual, contained tufts of linear ciliolated bracts within the involucre, without a trace of flowers. In the eleventh volume of the 'Linnæa,' 1837, p. 301, Von Cesati figures and describes an analogous case in _Carduus crispus_. The same author[1] records a similar instance in the umbel of _Seseli coloratum_, where the place of the flowers was occupied by stalked tufts of leaves. In the 'Gardeners' Chronicle,' October 6th, 1860, p. 894, is mentioned an instance where the blossoms of the pea were entirely absent, and their place supplied by accumulations of small, ovate, green scales, thus presenting an appearance similar to that brought about by the inordinate multiplication of the sepals in the "wheat-ear carnation," and in the Sweet William, and not unlike the condition met with in _Bryophyllum proliferum_. In _Digitalis purpurea_ a similar anomaly is sometimes met with. In the apple I have observed leafy shoots bearing terminal tufts of leaves where the flower should have been, so that what, under ordinary circumstances would be a corymb of flowers, is here represented by a series of tufts of leaves. In the cultivated azaleas also, leafy shoots occupying the position of the flower may occasionally be met with. In _Bouchea hyderabadensis_ I have seen the inflorescence more than usually branched and covered with little tufts of bracts, without a trace of true flower. A similar condition seems not infrequent in _Gentiana Amarella_, as I have not only met with the plant myself in this condition, but have been favoured with specimens by Mr. Pamplin, Mr. Darwin, and others. In _Phyteuma spicatum_ an analogous appearance has been recorded. Among Griffith's collections from Affghanistan is a species of willow (_Salix_) in which the inflorescence replaced by a much branched panicle, bearing a quantity of minute bracts, in the axils of which nestle numerous small buds. In another specimen the inflorescence preserves its usual catkin-like shape, but the flowers are replaced by little tufts of leaves. M. Germain de Saint Pierre mentions a case wherein the flowers of _Alisma parnassifolia_ were completely replaced by leaf-buds.[155] [Illustration: FIG. 79.--Spikelets of _Willedenovia_, composed entirely of scales to the exclusion of flowers.] [Illustration: FIG. 80.--Rose Willow, _Salix_, sp.] Here, also, may be mentioned the curious aggregations of scales which occur in some grasses, in _Restiaceæ_, _Juncaceæ_, and other orders, in which the inflorescence is made up of collections of scales or bracts with no trace of floral structure. Fig. 79 shows this in a species of _Willdenovia_, and a very good example is figured in a bamboo, _Pseudostachyum polymorphum_, by General Munro.[156] "Rose willows" (fig. 80) owe their peculiar appearance to a similar cause, the scales of the catkin being here replaced by closely crowded leaves. These aggregations of scales or leaves are not confined to the inflorescence, but may be found in other parts of the plant, and may be frequently met with in the willow, birch, oak, &c., generally as the result of insect puncture. On the other hand, the production of leaves or leaf-buds in place of flowers is, as is well known, generally the consequence of an excess of nutrition, and of the continuance rather than of the arrest of vegetative development.[157] It has even been asserted that a flower-bud may be transformed into a leaf-bud by removing the pistil at a very early stage of development, but this statement requires further confirmation.[158] =Viviparous plants.=--The spikelets of certain grasses are frequently found with some of their constituent parts completely replaced by leaves, like those of the stem, while the true flowers are usually entirely absent. A shoot, in fact, is formed in place of a series of flowers. In these cases it generally happens that the outermost glumes are changed, sometimes, however, even the outer and inner paleæ are wholly unchanged, while there is no trace of squamulæ or of stamens and pistils within them, but in their place is a small shoot with miniature leaves arranged in the ordinary manner. The grasses most commonly affected in this manner are _Dactylis glomerata!_, _Poa bulbosa!_, _Poa annua!_, _P. trivialis!_, _pratensis!_, _alpina!_, _angustifolia_, and _laxa_, _Cynosurus cristatus_, _Festuca nemoralis_, _F. ovina!_, _Glyceria fluitans!_, _Gl. aquatica_, _Aira alpina!_, _cæspitosa!_, _Phleum phalaroides_, _Lolium perenne!_, _Alopecurus pratensis!_, _Agrostis alba_, _Holcus mollis!_ [Illustration: FIG. 81.--Portion of panicle of _Aira vivipara_ and separate floret.] From an examination of the structure of viviparous grasses Von Mohl was led to the conclusion that the lower palea is to be considered as a bract, and not a perianthial leaf, because the base of the palea surrounds the stem or axis of the spikelet entirely, and both its margins cohere towards its lower extremity.[159] A similar condition occurs not infrequently in _Polygonum viviparum_, and in _Juncaceæ_, _Cyperaceæ_, &c. In the genus _Allium_ an analogous formation of little buds or bulbils takes place in lieu of flowers; this is specially the case with _A. vineale_, the flowers of which are rarely seen. Other illustrations of a similar character, where the adventitious leaf-buds are mixed in amongst the flower-buds, are cited under the head of Prolification of the Inflorescence. =Formation of buds on leaves.=--The formation of little bulbs upon the surfaces or edges of leaves, forming what are called viviparous leaves, has long been familiar to botanists amongst Alliums. Professor Alexander Braun,[160] who has paid much attention to this subject, divides cases of this kind according to the position of the buds; thus, for instance, they are sometimes formed upon the upper portion of the leaf or petiole, as in many ferns, in _Nymphæa guineensis_, some _Arads_, &c. The same condition has been met with as a teratological occurrence in the leaves of _Cardamine pratensis_, _Hyacinthus Pouzolzii_, _Drosera intermedia_,[161] _Arabis pumila_, _Chelidonium majus_, _Chirita sinensis_,[162] _Episcia bicolor_,[163] _Zamia_, &c.[164] Many species of _Begonia_ possess the power of emitting buds from the petioles and veins of the leaf; the little ramenta or scales which so plentifully beset the surface of some of these plants likewise, in some instances, pass gradually into leaves. _B. phyllomaniaca_, Mart., is the species best known as manifesting this tendency, but others have it also.[165] Buds are also very often formed upon the margins of the leaf, the best known instance of which occurs in _Bryophyllum calycinum_; Weinmann[166] figures an instance of this kind in _Alchemilla minima_, or they may occur upon the lower surface of the leaf, as in _Ornithogalum scilloides_ and _longe-bracteatum_. M. Duchartre[167] mentions a case in the tomato in which the leaves gave origin to small leaf-bearing branches, which, of course, must have originated from buds, just in the same way as in the _Drosera_ before mentioned. [Illustration: FIG. 82.--Formation of shoot on leaf of _Episcia bicolor_.] Gardeners occasionally avail themselves of this formation of buds from leaves to propagate plants, _e.g._ _Hoya_, _Gesnera_, _Gloxinia_, &c. =Formation of buds in the pith.=--This is said to be a normal condition in the curious _Stangeria paradoxa_,[168] and Mr. Berkeley records an instance of this in sea-kale[169] (fig. 83) where the crown had been injured, and buds were seen sprouting from its centre. [Illustration: FIG. 83.--Adventitious buds in sea kale.] [Illustration: FIG. 84.--Hyacinth bulb cut across to induce the formation of new bulbs.] [Illustration: FIG. 85.--Showing the formation of new bulbs on the cut edges of an old hyacinth bulb.] It will be remarked that the adventitious production of buds, like that of roots, is very often consequent on decay or injury. The Dutch bulb-growers have availed themselves of this latter circumstance in the propagation of hyacinths. Mr. Fortune, who published some articles on this subject in the 'Gardener's Chronicle,'[170] describes two special modes as adopted by these skilful horticulturists--the one to make two or three deep cuts at the base of the bulb, destroying the nascent flower-stalk when, after a time, small bulbs are formed along the edges of the cut surfaces (figs. 84, 85). The other method is effected by scooping out the interior of the base of the bulb, thus leaving exposed the cut ends of the sheathing leaves arranged concentrically; along these lines the new bulbs are, after some time, formed in great numbers (fig. 86). [Illustration: FIG. 86.--Showing the production of small bulbs on the inner surface of the scooped-out bulb of hyacinth.] For the formation of supernumerary leaves on the surface of the normal one, see Multiplication and Hypertrophy. =Production of gemmæ in place of spores.=--An instance of this is recorded by Dr. Montagne[171] in the case of a moss, _Encamptodon perichætialis_, in which, in the interior of the capsule, in lieu of spores numerous minute gemmæ of the same nature as those in the cup of _Marchantia_ were seen. =Formation of flowers on leaves.=--It is very doubtful whether a flower-bud has ever been found actually on a leaf. Mere adhesion of the pedicels of the leaf, such as happens in _Ruscus_, in _Helwingia_, _Erythrochiton hypophyllanthus_, and a few other plants, is, of course, not really to be considered in the light of an actual growth from the leaf, and it is very doubtful in the present state of our knowledge whether the case of the Nepaul barley should find a place here, but for convenience sake it is placed in this section, as it is uncertain at present where it properly belongs. [Illustration: FIG. 87.--Three-lobed end of outer palea of Nepaul barley bearing supplementary florets.] [Illustration: FIG. 88.--Three spikelets of Nepaul barley.] [Illustration: FIG. 89.--Lip of outer palea of Nepaul barley.] [Illustration: FIG. 90.--Supplementary rachillus or outer palea of Nepaul barley bearing florets.] [Illustration: FIG. 91.--Diagram showing arrangement of supplementary rachillus and florets.] [Illustration: FIG. 92.--Supplementary floret of Nepaul barley; palea removed.] This curious plant has been described and figured by Irmisch in the 13th volume of the 'Linnæa,' p. 124, t. iv; also by Professor Henslow, 'Hooker's Journal of Botany,' 1849, vol. i, p. 33, tabs. 2, 3. The lower palea of this plant forms an inverted flower-bud upon its midrib. In some fresh specimens which I have lately examined I find the structure to be as follows:--On each notch of the rachis there are three spikelets (fig. 88), each one-flowered, and each provided with two linear glumes; the outer palea in all cases is three-lobed at the summit, the central lobe being oblong and hollow, forming a kind of hood (figs. 87-89), and covered with hairs, which are directed downwards towards the centre of the plant. The two lateral lobes are more pointed than the central one; like it they are provided with hairs, but the hairs, in this case, are turned away from the centre of the plant. The cavity of the side lobes is generally empty, but that of the central lobe is occupied by a very slender stalk, which is apparently the termination of the midrib, but which is bent inwards at an acute angle, so as to occupy the hollow space (figs. 90-91). On this slender axis are developed two florets, more or less imperfect in their structure. Only one of the florets that I have seen contained a perfect ovary. The tips of the lateral lobes of the paleæ in the primary flower are sometimes extended into a long awn. A similar awn may also be occasionally found on the tips of the paleæ of the rudimentary florets. The occurrence of an adventitious axial structure with rudimentary flowers has been adduced in support of the opinion that the lower paleæ is, at least so far as its midrib is concerned, an axial rather than a foliar structure, but in the present uncertain state of our knowledge as to the morphology of grasses it is hazardous to risk any explanation founded on so exceptional a case as that of the Nepaul barley.[172] =Production of flower-buds in place of leaf-buds.=--Under natural circumstances this does not appear to be of so common occurrence as the change above alluded to, but by the art of the gardener the change is often effected. In rhododendrons and in peach trees and roses I have met with this change occurring without human agency. The means adopted by the gardener are such as check the luxuriance of the leaf-shoots,[173] and this is effected in various ways, as by continuous "pinching" or removal of the leaf-buds, by pruning, ringing the bark, confining the roots, limiting the supply of nutriment, and other means all based on the same principle. Some of the Cape bulbs (_Cyrtanthus_) are known not to produce their flowers till their leaves have received, in some manner, a check. Fires which often destroy the herbage thus have the effect of throwing the plant into bloom. A very remarkable instance is recorded of the production of flower-buds after an injury to the leaf-buds in the 'Bulletin of the Botanical Society of France,' vol. ix, p. 146. It appears that during the war of the French against the Arabs in Algiers, the latter planted several hundreds of Agaves with a view to obstruct the passage of the French cavalry. The soldiers hacked these plants with their sabres, and cut out the central tuft of leaves, or the heart, as gardeners call it. The following season almost every one of these Agaves sent up their large handsome flower-spikes. It is well known that, under ordinary circumstances, these plants do not flower except at long intervals of time. =Presence of flowers on spines.=--That the spine, as a contracted branch, should occasionally produce flowers is not to be wondered at, though the occurrence is by no means common. M. Baillon showed at a meeting of the Botanical Society of France ('Bulletin,' vol. v, 1858, p. 316) a branched spine of _Gleditschia_ bearing a flower at the end of each of the sub divisions. This was, therefore, strictly analogous with those cases in which the peduncle is normally spiney. =Formation of flower-bud on the petals.=--An instance of this, it is believed, the only one on record, is cited in the 'Gardeners' Chronicle' for 1865, p. 760, by the Rev. M. J. Berkeley, who describes the formation of a flower-bud on the surface of a petal of _Clarkia elegans_. Reasoning from analogy there seems no reason why buds should not be formed on the petals as well as on the leaves. =Formation of buds on fruits.=--This is a point of some moment with reference to the share which the axis takes in the production of "inferior" fruits. A very frequent malformation in pears is one wherein a second pear proceeds from the centre of the first, and even a third from the centre of the second.[174] Pears are occasionally also observed arising either from the axils of the sepals of the primary pear or from the axil of leaves originating on the outer surface of the fruits--using the term fruit in its popular sense. These cases afford strong confirmation of the view that the outer portion of the so-called fruit in these plants is rather to be considered as an expansion and hollowing-out of the flower-stalk, than as formed from the calyx-tube. It is noteworthy that the true carpels and seeds are frequently entirely absent in these cases.[175] Further reference to these fruits will be made under the head of Hypertrophy. M. Trécul has described and figured an instance in a species of _Prismatocarpus_, in which a second flower proceeded from the axil of a bract attached to the side of the fruit of the first flower.[176] A similar growth was observed in the fruit of _Philadelphus speciosus_ by M. A. Gris, who observed that the so-called calyx-tube was provided with two small bracts, from the axil of one of which proceeded a small flower-bud.[177] [Illustration: FIG. 93.--Small buds projecting from the edges of the fruit in _Opuntia_.] The fruits of _Opuntia Salmiana_, _O. fragilis_,[178] _O. monacantha_, and of some species of _Echinocactus_, have been observed to form small fruit-like branches around their summits. M. Napoléon Doumet describes the fruit as ripening as usual, but as being destitute of seeds in the interior; after a little while the fruit begins to wither, and then a circle of small buds, like those of the stem, may be seen at the top of the fruit, each bud springing from the axil of a little tuft of wool and spines found on the fruit. These little buds elongate into long shoots, produce flowers the following year, which flowers exhibit the same peculiarity. Gasparini and Tenore are said to have recorded the same fact as long since as 1832. The specimen from which the figure (fig. 93) was taken produced its fruits in the Royal Gardens at Kew, and is now preserved in the museum of that establishment. The adventitious growth in these cases appears to arise from the tufts of spines, which, it has been suggested, are the homologues of the sepals. There can, however, be little doubt that the outer and lower portion of the fruit of _Opuntia_ and its allies is a dilatation of the flower-stalk. This is borne out by the fruits of _Pereskia_, which bear leaves on their surface arranged spirally; indeed, the fruits of _Pereskia Bleo_ are mentioned as producing buds from their summits, in the same way as the _Opuntia_ just cited. _P. Bleo_ is said, by M. Delavaud,[179] to present this anomaly as a constant occurrence. On the summit of the primary fruit, arising apparently from the axils of the sepals, or of small leafy bracts in that situation, are a series of fruit-like branches, which, in their turn, are surmounted by others, even to the fourth generation. The fruits of _Tetragonia expansa_ frequently have attached to their side a secondary flower or fruit in such a position as to lead to the inference that it springs from the upper portion of the peduncle which is dilated to invest the true carpels. In other instances it is due to an adhesion of the pedicel to the side of the fruit. In either case the production of an adventitious bud might be considered as an illustration of prolification of the inflorescence, though not as was supposed by Moquin and others of axillary prolification.[180] Buds have also been produced artificially on the surface of some of the fruits in the construction of which the axis is supposed to share; thus, the unripe fruits of some species of _Lecythis_ were stated by Von Martius, at a meeting of the German Naturalists at Carlsruhe, to produce buds when placed in the earth. The fruit of these plants is probably of the same nature as that of the _Pomaceæ_, and Baillon[181] succeeded in producing buds on the surface of the inferior ovary of _Jussiæa_. Some of the cases just mentioned have been considered to be instances of prolification of the fruit, but the fruit has little to do with the appearances in question. =Formation of adventitious flowers and fruits within the ovary.=--This generally arises either from substitution of a flower-bud for an ovule or from prolification; there are certain cases, however, where the new growth seems not to be either due to metamorphosis or to prolification strictly. The cut, fig. 94, represents a case where, in the dilated upper portion of the ovary of _Sinapis arvensis_, two flower-buds were found projecting from a raised central line, corresponding, as it would seem, to the midrib, and not to the margins of the carpel. Similar cases have occurred in _Nasturtium amphibium_, _Brassica Rapa_, and _Passiflora quadrangularis_. [Illustration: FIG. 94.--Distended pod of _Sinapis arvensis_ bearing in the interior stalked flower buds.] In Bromfield's 'Flora Vectensis,' p. 35, the following account is given of an abnormal development in _Cardamine pratensis_: "On the lower part of the corymb were several seed vessels on pedicels changed from their usual linear to an ovate elliptical figure, so as to resemble a silicula. These, on being opened, were found to contain petals of the usual colour, which in the pods above had burst from their confinement and appeared as semi-double flowers; the valves of the pod answering to the true calyx. * * * From their verticillate arrangement it is evident that these petaloid expansions were not transformed seeds, but simply a development of the common axis within the ovary into an abortive whorl of floral organs, besides which there were evident rudiments both of stamens and germens in the centre of the bundle." Baillon[182] also records a case of the same nature in _Sinapis arvensis_. [Illustration: FIG. 94*.--Portion of the interior of the silicle in _Cheiranthus Cheiri_, showing adventitious pod in the place of an ovule.] [Illustration: FIG. 95.--Adventitious pod from fig. 94, enlarged.] Here, too, may also be mentioned the presence of an adventitious siliqua within the ordinary one attached along the same line as the ovules, and partially divided by a replum into two cavities. In this case there was nothing to indicate the presence of floral envelopes (figs. 94, 95). A similar occurrence has been brought under my notice in some grapes which were observed to be cracking before they were perfectly ripe, and in which adventitious fruits were found within the parent grape, occupying the position of seeds (figs. 96, 97). Similar anomalous growths are noticed under the heads of Substitution and Prolification. =Formation of stamens within the cavity of the ovary.=--The only instance of this that has come under the author's observation occurred in some flowers of _Bæckea diosmæfolia_, Rudge, for an examination of which he is indebted to Mr. Bentham. [Illustration: FIG. 96.--Section of Barbarossa grape showing adventitious grape in the position of a seed.] [Illustration: FIG. 97.--Grape with supplementary fruit in the interior] In the normal flower there is a turbinate hollow calyx, whose limb is divided into five serrated lobes; alternating with these latter, and springing from the throat of the calyx, are the petals. Originating from the same annular disk as the petals are the stamens, seven or eight in number. The ovary is partially adherent, is surmounted by a style, and has two or three loculi with an axile placenta, to which several small curved ovules are attached. The malformed flowers did not present anything peculiar in their outer parts, nor did the ovary, partially immersed within the expanded top of the flower-stalk and the calyx-tube, which is continuous with that organ, show externally any indication of the change within. On cutting it across, however, in any direction, numerous perfect stamens (filaments and anthers) were seen projecting from the walls of the cavity (fig. 98). In most of the flowers the ovary was one-celled; but in a few there was the usual axile placenta; yet even in these latter cases the stamens originated from the walls of the cavity, and not from the placenta. The stamens presented different degrees of development; in some cases they were fully formed, the anther-lobes open, and the pollen exposed; while in other instances the filaments were involute or circinate, just as the ordinary stamens are in the unexpanded flower-bud. In some cases imperfect stamens were found, mere barren filaments, with or without rudimentary anthers at the top. In no instance was there a perfect ovule, or, indeed, any trace of ovules. The stamens appeared to be arranged irregularly on the walls of the ovarian cavity; and while they were certainly more numerous at the lower portion (that now generally considered to be formed by the cup-like end of the pedicel), they were not wanting in the upper half of the ovary (or that which is probably formed from the carpellary leaves). [Illustration: FIG. 98.--1. Vertical section of flower of _Bæckea diosmæfolia_, showing stamens within the ovary; magnified ten times. 2. Transverse section of ovary. 3. Stamen. 4. Imperfect stamen.] This case differs from most that have been recorded, and in which there has been a more or less complete substitution of anther for carpel, or where the tissues of the carpel have produced pollen, and so taken upon themselves the appearance and functions of anthers. Instances of this latter kind are not uncommon; but in the _Bæckea_ there were perfect stamens proceeding from perfect and completely closed ovaries. Moquin-Tandon[183] cites from Agardh an instance which seems more closely to resemble the state of things in the _Bæckea_, and which occurred in a double hyacinth, wherein both anthers and ovules were borne on the same placenta. Probably, though the fact is not stated, the ovary of the hyacinth was open; and we are told that the flower was double--that it was, in fact, modified and changed in more organs than one; while in the _Bæckea_ nothing at all unusual was observed till the ovary was cut open. The style was present even in those flowers where there was no axile placenta; hence in these cases it could not be, as Lindley stated it to be in the closely allied _Babingtonia_, a prolongation of the placenta.[184] =Formation of pollen within the ovules.=--This has now been recorded in two instances by Mr. S. J. A. Salter in _Passiflora cærulea_ and in _P. palmata_,[185] and by the author in _Rosa arvensis_.[186] [Illustration: FIG. 99.--Pollen within the ovule of _Passiflora_ (after Salter).] In the case of the passion-flower there were various malformations in the ovaries, which were all more or less split open at the distal end, indicating a tendency towards dialysis. The pollen-bearing ovules were borne on the edges of these ovaries, and presented various intermediate conditions between anthers and ovules, commencing at the distal extremity of the carpel with a bi-lobed anther, and passing in series to the base of the ovary, an antheroid body of ovule-like form, a modified ovule containing pollen, an ovule departing from a perfectly natural condition only in the development of a few grains of pollen in its nucleus, and, finally, a perfect, normal ovule. In the flowers of the Rose the stamens exhibited almost every conceivable gradation between their ordinary form and that of the carpels, while some of the ovules contained pollen in greater or less abundance. Speaking generally, the most common state of things in these flowers was the occurrence on the throat of the calyx, in the position ordinarily occupied by the stamens, and sometimes mingled with those organs, of twisted, ribbon-like filaments, which bore about the centre one or more pendulous, anatropous ovules on their margins. Immediately above the latter organs were the anther-lobes, more or less perfectly developed, and surmounting these a long style, terminating in a fringed, funnel-shaped stigma. Sometimes the ovules were perfect, at other times the nucleus protruded through the foramen, while in a third set the nucleus was included within the tegument, the ovules having in all respects their natural external conformation, containing, however, not only pollen-grains, but also a layer of those peculiar spheroidal cells, including a fibrous deposit, which are among the normal constituents of the anther. In one case, where the coat of the ovule was imperfect, and allowed the nucleus to protrude, the pollen was evidently contained within the central mass of the structure. In this instance the fibrous cells were not detected, these being only found in cases where the investment of the ovule was perfect; and hence it seems likely that the fibrous cells were part of the coat of the ovule, while the pollen was formed within the nucleus. In no case was any trace of embryo sac to be seen. The main interest, as Mr. Salter remarks, in these cases is physiological; so far as structure alone is concerned, there does not appear any reason why pollen-grains should not be developed in any portion of the plant; the mother cells in which the pollen is formed not differing, to all outward appearance, from any other cells, unless it be in size. The fundamental unity of construction in all the organs of plants could hardly be better illustrated than by these cases; while, in spite of their exceptional nature, they must be of great interest physiologically, as showing the wide limits of possible variation which thus may even involve the sex, "for an ovule to develop pollen within its interior," says Mr. Salter, "is equivalent to an ovum in an animal being converted into a capsule of spermatozoa. It is a conversion of germ into sperm, the most complete violation of individuality and unity of sex. * * * * The occurrence of an antheroid ovule and a normal ovule on the same carpellary leaf realises the simplest and the most absolute form of hermaphroditism." It must, however, be remarked that the term substitution would be preferable to conversion. There is, at present, no evidence to show that the germinal vesicles were present in these cases; on the other hand, it seems most probable that they were not, so that the presence of the pollen-cells must be considered as simply adventitious. It can hardly be that they were, in the first instance, germinal vesicles, which, in course of time, became so modified as to assume the appearance of pollen-grains. Between the nucleus of the ovule and the tubercle of cellular tissue constituting the primordial anther, there is little or no difference, so that it may be said that, for a time, there is no distinction of sex in the nascent flower, but as development goes on, the difference becomes perceptible. It cannot at present be stated what precise circumstances induce the one mass to form mother-cells and pollen-grains, and the other to develop an embryo sac and germinal vesicles. Position and external circumstances may have some indirect effect, and it may, perhaps, be significant that in all the instances of polliniferous ovules, the ovular structures have been exposed on an open carpel or otherwise, in place of being confined within the cavity of a closed ovary, as under ordinary circumstances. Even among Conifers the ovuligerous scales are so closely packed that there is little or no exposure of the ovules. But, apart from all speculative notions as to the relation between the structure and functions of the anther and of the ovule respectively, and of the possibility or the reverse of parthenogenesis, it will clearly be necessary in any future alleged occurrence of the latter phenomenon to ascertain whether any or all of the apparent ovules are, or are not, anthers in disguise. =Homomorphic flowers of "Compositæ."=--In a large section of the _Compositæ_ there is, as is well known, a distinction between the florets of the "disc" and those of the "ray," the latter being ligulate, the former tubular. In what are erroneously called double flowers in this order, _e.g._ in the Chrysanthemum, Dahlia, &c. &c., the florets are all ligulate. This change is sometimes classed with peloria, but there is no abnormal regularity in these cases. On the other hand, were the ligulate florets to be all replaced by tubular ones, the term peloria would be more strictly applicable. It will be remembered that in the sub-order _Ligulifloræ_, the florets are naturally all ligulate, so that the change above mentioned is not in itself a very grave one. =Heterotaxy affecting the inflorescence.=--Under the head of Prolification, Heterogamy, &c., various deviations from the normal inflorescence are alluded to. In this place, therefore, it is only necessary to mention certain rare deviations from the customary arrangement of the inflorescence, such as the change from a definite centrifugal form of inflorescence to an indefinite centripetal one. This occurs occasionally in roses, where the shoot, instead of terminating in a flower-bud, lengthens and bears the flower-bud on its sides as in a raceme. In the hyacinth, the inflorescence of which is properly indefinite, the terminal flower may frequently be found to expand first, though in order of development it may have been the last formed. It occasionally happens that certain plants will, contrary to their usual custom, bloom twice in the same season; this usually arises from the premature development of buds which, under ordinary circumstances, would not unfold till the following spring. In these instances of what the French term "fleuraison anticipée," the position of inflorescence is not changed, but there are other cases where the position of the inflorescence is altered, as in the laburnum, where, in some seasons, racemes may be seen springing from short lateral "spurs" along the sides of the branches, as well as from the extremities of long shoots. Of a similar nature are those cases wherein stems or branches usually sterile become fertile; this happens in _Equisetaceæ_,[187] in _Restiaceæ_, and other orders. In the equisetums, the condition in question has been specially noticed to occur after prolonged drought. _Equisetaceæ_ are likewise subject to an anomaly called by Duval Jouve interruption of the spike, and wherein the scales bearing the spore cases are separated by whorls of branches instead of forming one compact unbroken spike as usual. This alternation of the organs of vegetation and reproduction may also be seen occasionally in _Typha_, and other plants. Kirschleger describes a case in which the male catkins of _Salix cinerea_ were placed at the ends of the branches instead of being lateral productions; moreover the usual articulation was not formed, so that the catkin was persistent instead of deciduous.[188] =Supra-soriferous ferns.=--In the great majority of ferns the sori or clusters of spore cases are placed on the under surface of the fronds; nevertheless, a few cases are on record where the fructification is produced on the upper as well as on the lower surface, and sometimes abundantly so. This occasionally happens from the elongation of the normally placed sorus, which thus extends to the margin, and returns on the upper side, when the sori chance to be placed opposite to the marginal crenatures. But it is also frequently the case that the sori are produced on the upper side, distinctly within the margin, and where there are no corresponding sori beneath. Those varieties which have the margin crenated or lobed seem most liable to assume this abnormal supra-soriferous condition. Among the ferns in which this condition has been observed are the following: _Scolopendrium vulgare_, _Polypodium anomalum_, Hook., _Asplenium Trichomanes_, _Cionidium Moorei_.[189] FOOTNOTES: [147] 'Gard. Chron.' 1852, p. 51. [148] 'Flora.' 1858, pp. 32-42. [149] 'Journ. Linn. Soc.,' vol. vi; "Botany," 1862, p. 24. [150] 'Tijdschrift voor Natuur. Geschied,' 1836, vol. iii, tab. vii, p. 171. [151] Roeper, 'Enum. Euphorb.,' p. 19. Bernhardi, 'Linnæa,' vii, p. 561, tab. xiv, f. 1. Wydler, "Subcotyled. sprossbildung," 'Flora,' 1850, p. 337. Hooker, 'Trans. Linn. Soc.,' vol. xxiv, p. 20 (_Welwitschia_). [152] 'Misc. Austriac. ad Bot.,' vol. i, p. 133, t. 5. [153] See also Carrière, 'Revue Horticole,' 1866, p. 442; and as to pears, Radlkofer in 'Bericht über die Thätigkert der Baierischen Gartenbau Gesellschaft,' 1862, p. 74, t. i. [154] 'Flora Indica,' p. 23. [155] 'Bull. Soc. Bot. Fr.,' 1856, p. 53. [156] 'Trans. Linn. Soc.' xxvi, p. 142, tab. iv, B. [157] "Si arbusculam, quæ in ollâ antea posita, quotannis floruit et fructus protulit, deinde deponamus in uberiori terra calidi caldarii, proferet illa per plures annos multos ac frondosos ramos, sine ullo fructu. Id quod argumento est, folia inde crescere, unde prius enati sunt flores; quemadmodum vicissim, quod in folia nunc succrescit, id, naturâ ita moderante, in flores mutatur, si eadem arbor iterum in ollâ seritur."--Linnæus, 'Prolepsis,' § iii. [158] 'Rev. Hortic.' May, 1868, 'Gardeners' Chronicle,' 1868, pp. 572, 737. [159] Cited in 'Annals Nat. Hist.,' 1845, vol. xv, p. 177. [160] 'Ann. Scienc. Nat.,' vol. xiv, 1860, p. 13. [161] Naudin, 'Ann. Sc. Nat.,' 2nd ser., 1840, vol. xiv, p. 14, fig. 6, pl. i (_Drosera_). St. Hilaire, 'Comptes Rendus,' ix, p. 437. [162] Hance, 'Hook. Journ. Botany,' 1849, vol. i, p. 141, pl. v. [163] Booth, 'Gard. Chron.,' Jan. 1st, 1853, p. 4. [164] Lindley, 'Theory of Horticulture,' ed. 2, p. 273. [165] 'Hook. Journ. of Botany,' 1852, iv, p. 206. See also the curious _Begonia gemmipara_, 'Hook. fil. Illust. Himal. Plant.,' t. xiv. [166] 'Phytanth.,' n. 36, _d._ [167] 'Ann. Scienc. Nat.,' 3rd series. 1853. vol. xix, p. 251, tab. 14. [168] Carrière, 'Revue Horticole.' 1868, p. 184. [169] 'Gard. Chron.,' 1858, p. 556. [170] 1863, p. 556, &c. [171] 'Ann. Nat. Hist.,' 1845, vol. xvi, p. 355. [172] See also Lindley, 'Veg. Kingd.,' p. 109 et 116_a_, where the views of Raspail, R. Brown, Mohl, Henslow, and others, are discussed. [173] It has been observed that if a plant is supplied with copious nourishment the flowering-period is delayed; but that moderate or even scanty nourishment accelerates it. Goethe, 'Metam.,' § 30. See also Wolff, 'Theoria Generationis,' 1759; Linn. 'Prolepsis,' §§ 3 and 10. [174] Moquin-Tandon, p. 384; also Lindl., 'Elements of Botany,' p. 65, fig. 130; "Theory of Horticulture," p. 86. 'Gard. Chron.,' 1851, p. 723; Irmish, 'Flora,' 1858, p. 38, &c. [175] Caspary, 'Bull. Soc. Bot. Fr.,' vol. vi, 1859, p. 235; also Payer, ibid., vol. i, 1854. p. 283. [176] Trécul, 'Ann. Sc. Nat.,' 2nd ser., vol. xx, p. 339. [177] 'Bull. Soc. Bot. Fr.,' vol. vii, 1858, p. 331. [178] 'Bull. Soc. Bot. Fr.,' vol. i. p. 306, vol. v, p. 115. 'Illustr. Hortic.,' xii, 1865, Misc. 79. 'Rev. Horticole,' 1860 p. 204, et 1867 p. 43. [179] 'Bull. Soc. Bot. Fr.,' 1858, p. 685. [180] The structure of this flower is discussed at some length in a paper by the author on axillary prolification. 'Trans. Linn. Soc.,' vol. xxiii, p. 486, t. liv. fig. 3. See also 'Clos. Bull. Soc. Bot. Fr.,' vol. v, 1855, p. 672. Seringe et Heyland, 'Bull. Bot.,' i, p. 8. 'Pallas Enum. Plant. Hort. Demidoff,' append, c, ic. [181] 'Adansonia,' i, 181. [182] 'Adansonia.' vol. iii, p. 351, tab. xii. [183] 'Elém. Térat. Végét.,' p, 218. [184] Masters, 'Journ. Linn. Soc.,' vol. ix, 1866, p. 334. [185] 'Trans. Linn. Soc.,' vol. xxiv, p. 143. tab. xxiv. [186] 'Brit. Assoc. Report,' Dundee, 1867; and Seemann's 'Journal of Botany,' 1867, p. 319, tab. lxxii, figs. B 1-9. [187] Duval Jouve, 'Hist. Equiset. France.' 1864, p. 154. [188] 'Flora,' t. xxiv, 1841, p. 340. [189] Moore, 'Nature-Printed British Ferns,' 8vo edition, vol. ii. p. 135. tab. lxxxv, B, &c. CHAPTER IV. HETEROGAMY. This term is here intended to apply to all those cases in which the arrangement of the sexual organs is different from what it is habitually. It is evident that in many instances there is no malformation, no monstrosity, but rather a restoration of organs habitually suppressed, a tendency towards structural completeness rather than the reverse. It must be also understood that the following remarks apply to structural points only, and are not intended to include the question of function. The occurrence of heteromorphic unions renders it necessary to keep in mind that plants hermaphrodite as to structure are by no means necessarily so as to function. The simplest case of this alteration in the relative position of the sexes is that which occurs in monoecious plants, where the male and female flowers have a definite position, but which in exceptional instances is altered. =Change in the relative position of male and female flowers= may thus occur in any monoecious plant. Cultivated maize, _Zea Mays_, frequently exhibits alterations of this kind; under ordinary circumstances, the male inflorescence is a compound spike, occupying the extremity of the stem, while the female flowers are borne in simple spikes at a lower level, but specimens may now and then be found where the sexes are mixed in the same inflorescence; the upper branching panicle usually containing male flowers only, under these circumstances, bears female flowers also.[190] In like manner, but less frequently, the female inflorescence occasionally produces male flowers as well. Among the species of _Carex_ it is a common thing for the terminal spike to consist of male flowers at the top, and female flowers at the base; the converse of this, where the female flowers are at the summit of the spike, is much more uncommon. An illustration of this occurrence is given in the figure (fig. 100). Among the _Coniferæ_ numerous instances have been recorded of the presence of male and female flowers on the same spike, thus Mr. now Professor Alexander Dickson exhibited at the Botanical Society of Edinburgh in July, 1860, some malformed cones of _Abies excelsa_, in which the inferior part of the axis was covered with stamens, whilst the terminal portion produced bracts and scales like an ordinary female cone. The stamens of the lower division were serially continuous with the bracts above. Some of the lower scales of the female portion were in the axils of the uppermost stamens, which last were somewhat modified, the anther cells being diminished, whilst the scale-like crest had become more elongated and pointed, in fact, more or less resembling the ordinary bracts.[191] Mohl, Schleiden, and A. Braun have observed similar cones in _Pinus alba_, and Cramer figures and describes androgynous cones in _Larix microcarpa_. C. A. Meyer ('Bull. Phys. Math.,' t. x, 1850) also describes some catkins of _Alnus fruticosa_ which bore male flowers at the top, and female flowers at the base. [Illustration: FIG. 100.--Spike of _Carex acuta_, with female flowers at the summit.] On the subject of this section the reader may consult A. Braun,. 'Das Individ.,' 1853, p. 65. Caspary, 'De Abietin. flor. fem. struct. morphol.' Schleiden. 'Principles,' English edition, p. 299. Mohl, 'Verm. Schrift.,' p. 45. Meyen in 'Wiegm. Archiv.,' 1838, p. 155. Cramer, 'Bildungsabweich,' p. 4, tab. v, figs. 13-17. Parlatore, 'Ann. Sc. Nat.,' ser. iv, vol. xvi, p. 215, tab. 13A. See also under the head of Prolification, Substitutions, &c. =Change from the monoecious to the dioecious condition.=--This is of less frequent occurrence than might have been anticipated. In the 'Gardeners' Chronicle,' 1847, pp. 541 and 558, several instances are noted of walnut trees bearing female flowers to the exclusion of males. The mulberry tree has also been noticed to produce female blossoms only, while in other plants male flowers only are developed. It seems probable that the age of the plant may have something to do with this production of flowers of one sex to the exclusion of the other. =Change from the dioecious to the monoecious condition.--Androgynism.=-- This is of far more common occurrence than the preceding. [Illustration: FIG. 101.--Monoecious inflorescence of Hop.] In the hop (_Humulus Lupulus_), when monoecious, the female catkins are usually borne on the ends of the branches as shown in the cut (fig. 101), and a similar thing has been noticed in _Urtica dioica_ by Clos, 'Bull. Soc. Bot. France,' vol. 9, p. 7. Baillon ('Etudes du groupe des Euphorbiacées,' p. 205) mentions the following species of that order as having been seen by him with monoecious inflorescence: _Schismatopera distichophylla_, _Mozinna peltata_, _Hermesia castaneifolia_. Oliver mentions ('Hook. Icon. Plant.,' t. 1044) that in _Leitneria floridana_ the upper scales of the male catkin occasionally subtend an ovary. It would seem that external conditions have some effect in determining the formation of one sex, as in some species of _Carex_, while in the case of _Salix repens_, Hampe[192] says that when grown partially or for a time under water, those twigs which are thrust up above the surface bear female flowers, while those twigs that blossom after the water is dried up, produce male flowers only. Carrière[193] says that a plant of _Stauntonia latifolia_ which for some years produced stamens only, now produces flowers of both sexes; it was dioecious, but is now monoecious. The same author alludes to a similar occurrence in _Juniperus Virginiana_. The hops is also said to vary in sexual characteristics from time to time.[194] In addition to the genera, already named, in which this production of flowers of both sexes has been observed may be mentioned _Taxus! Gunnera! Urtica! Mercurialis! Restio! Cannabis! Salix! Humulus!_ as well as others in which the change is less frequent. Among cryptogams a similar change occurs. As an illustration may be cited _Leucobryum giganteum_, as quoted from Müller in Henfrey's 'Botanical Gazette,' i, p. 100. As to androgynous willows, in addition to the references given under the head of Substitution of stamens for pistils, see Schlechtendal, 'Flora Berol.,' ii. p. 259. Tausch, 'Bot. Zeit.,' 1833, i. p. 229. Koch, 'Synops. Flor. Germ.,' 740. Host, 'Flor. Aust,.' ii, p. 641 (_S. mirabilis_). See also Hegelmaier, 'Württemberg Naturwissenshaft Jahreshefte,' 1866, p. 30. Other references to less accessible works are given in 'Linnæa,' xiv, p. 372. =Change from hermaphroditism to unisexuality.=--Many flowers ordinarily hermaphrodite as to structure, become unisexual by the abortion or suppression of their stamens, or of their carpels, as the case may be. This phenomenon is lessened in interest since the demonstration of the fact by Darwin and others, that many plants, structurally hermaphrodite, require for the full and perfect performance of their functions the cooperation of the stamens and pistils, belonging to different individuals of the same species. Some of the _Ranunculaceæ_ constantly exhibit a tendency towards the dioecious condition, and the rarity with which perfect seeds of _Ranunculus Ficaria_ are formed is to be attributed, in great measure, to the deficiency of pollen in the anthers of these flowers. _Ranunculus auricomus_ also is frequently sterile. Specimens of _Ranunculus bulbosus_ may be met with in which every flower is furnished with carpels, most of which have evidently been fertilised, although there are no perfect stamens in the flowers. Knight and other vegetable physiologists have been of opinion that a high temperature favours the production of stamens, while a lower degree of heat is considered more favorable to the production of pistils, and in this way the occurrence of "blind" strawberries has been accounted for. Mr. R. Thompson, writing on this subject, speaks of a plantation of Hautbois strawberries which in one season were wholly sterile, and accounts for the circumstance as follows: the plants were taken from the bearing beds the year previous, and were planted in a rich well-manured border, in which they started rapidly into too great luxuriance, the growth being to leaves rather than to fruit. The following season these same plants bore a most abundant crop, hence these plants were accidentally prevented from perfecting their female organs.[195] Mr. Darwin[196] cites from various sources the following details relating to strawberries which it may be useful to insert in this place, as throwing some light upon the production of unisexual flowers. "Several English varieties, which in this country are free from any such tendency, when cultivated in rich soils under the climate of North America commonly produce plants with separate sexes. Thus, a whole acre of Keen's seedlings in the United States has been observed to be almost sterile in the absence of male flowers; but the more general rule is, that the male plants over-run the females.... The most successful cultivators in Ohio plant, for every seven rows of pistillate flowers, one row of hermaphrodites, which afford pollen for both kinds; but the hermaphrodites, owing to their expenditure in the production of pollen, bear less fruit than the female plants." _Stratiotes aloides_ has been said to produce its carpels with greater abundance towards the northern limits of its geographical distribution, and its stamens, on the other hand, are stated to be more frequently developed in more southern districts. _Honckenya peploides_ affords another illustration of the sexual arrangements in the flower being altered as it would seem by climatal conditions. Thus, in the United States, according to Professor Asa Gray, the flowers are frequently hermaphrodite, while in this country they are usually sub-dioecious.[197] Treviranus[198] says that the flowers of _Hippuris_ and _Callitriche_ are apt to be hermaphrodite in summer, but female only at a later period. For further remarks on this subject, see sections relating to suppression of stamens and pistils. =Change from unisexuality to hermaphroditism.=--This occurrence depends on one of two causes, either organs are developed (stamens or pistils as the case may be), which are habitually absent in the particular flower; or some of the stamens may be more or less completely converted into or replaced by pistils, or _vice versâ_. The first condition is the opposite of suppression; it is, as it were, a restoration of symmetry, and might be included under the head of regular peloria, inasmuch as certain organs which habitually undergo suppression at a certain stage in their development, by exception, go on growing, and produce a perfect, instead of an imperfect flower. In teratological records it is not always stated clearly to which of the two above-named causes the unusual hermaphroditism belongs, though it is generally easy to ascertain this point. Very many, perhaps all, diclinous flowers may, under certain conditions, become perfect, at least structurally. I have myself seen hermaphrodite flowers in _Cucurbita_,[199] _Mercurialis_, _Cannabis_, _Zea Mays_, and _Aucuba japonica_, as well as in many _Restiaceæ_, notably _Cannamois virgata_ and _Lepyrodia hermaphrodita_. _Spinacia oleracea_, _Rhodiola rosea_, _Cachrys taurica_, and _Empetrum nigrum_ are also occasionally hermaphrodite. Gubler[200] alludes to a similar occurrence in _Pistacia Lentiscus_, wherein, however, he adds that there was a deficiency of pollen in the flowers. Schnizlein[201] observed hermaphrodite flowers in the beech, _Fagus sylvatica_, the ovaries being smaller than usual, and the stamens epigynous. Baillon[202] enumerates the following _Euphorbiaceæ_ as having exceptionally produced hermaphrodite flowers, _Crozophora tinctoria_, _Suregada_ sp., _Phyllanthus longifolius_, _Breynia_ sp., _Philyra brasiliensis_, _Ricinus communis_, _Conceveiba macrophylla_, _Cluytia semperflorens_, _Wall_, non _Roxb_. _Mercurialis annua_ and _Cleistanthus polystachyus_. In some of these cases the hermaphroditism is due to the development of anthers on the usually barren staminodes, though, in other cases, the stamens would seem to be separate, independent formations, as they do not occupy the same relative position that the ordinary stamens would do if developed.[203] [Illustration: FIG. 102.--Flower of _Fuchsia_ in which the calyx was leafy, the petals normal (reflexed in the figure), the stamens partially converted into ovaries, the ordinary inferior ovary being absent. See Substitution.] Robert Brown[204] observed stamens within the utricle of _Carex acuta_, and Gay is stated by Moquin ('El. Ter. Veg.,' p. 343) to have observed a similar occurrence in _Carex glauca_. Paasch[205] observed a similar occurrence in _C. cæspitosa_, and Schauer, in _C. paludosa_,[206] though in the latter instance the case seems to have been one of transformation or substitution rather than one of hermaphroditism. The second cause of this pseudo-hermaphroditism is due either to the more or less perfect mutation of male and female organs, or it may be to the complete absence of one and its replacement by another, as when out of many stamens, one or more are deficient, and their places occupied by carpels. This happens very frequently in willows and poplars, and has been seen in the beech.[207] [Illustration: FIG. 103.--Hermaphrodite flower of _Carica Papaya_.] In _Begonia frigida_[208] the anomaly is increased by the position of the ovaries above, the perianth, a position due, not to any solution or detachment of the latter from the former, but simply to the presence of ovaries where, under ordinary circumstances, stamens only are formed, as happened also in a garden variety of a _Fuchsia_, wherein, however, the change was less perfect than in the _Begonia_, and in which, as the flower is naturally hermaphrodite, the alteration is of the less importance. [Illustration FIG. 104.--Ovuliferous anthers--_Cucurbita_.] In hermaphrodite flowers of _Carica Papaya_ (fig. 103) there is a single row of five stamens instead of two rows of five each as in the normal male flowers, the position of the second or inner row of stamens being occupied by five carpels, which, however, are not adherent to the corolla as the stamens are, thus, supposing the arrangement of parts in the normal male flowers to be as follows: --------------------------- s s s s s --------------------------- | p p p p p | st st st st st | st st st st st | That of the hermaphrodite blossoms would be, in brief, as follows: | 5 s |------------ | 5 p | 5 st | 5 c | One of the most curious cases of this kind recorded is one mentioned by Mr. Berkeley,[209] wherein a large white-seeded gourd presented a majority of flowers in which the pollen was replaced by ovules. It would seem probable from the appearances presented by the figure that these ovules were, some of them, polliniferous, like those of the _Passiflora_, &c., described at p. 185, but nothing is stated on the subject. See also section on Regular Peloria, Substitution, Pistillody of the stamens, &c. FOOTNOTES: [190] See also Clos., 'Mem. Acad. Toulouse,' sixth ser., t. iii, pp. 294-305. Scott, 'Trans. Bot. Soc. Edinburgh,' t. viii, p. 60. Wigand, 'Flora,' 1856, p. 707. [191] Professor Dickson concludes from the examination of these structures that the male cone, consisting of simple stamens developed on one common axis, must be regarded as a simple male flower, while the axillary scales of the female cone are by him compared with the flattened shoots of _Ruscus_. [192] 'Linnæa,' xiv, 367. [193] Rev. Hortic.,' January, 1867. [194] See Royle, 'Man. Materia Medica,' ed. 1, p. 567. [195] Thomson, 'Gardener's Assistant,' p. 577. [196] 'Variation of Animals and Plants,' i, 353. [197] Babington, 'Ann. Nat. Hist.,' vol. ix, 1852, p. 156. [198] 'Phys. der Gewächse,' ii, p. 323. [199] See also Schlechtendal, 'Linnæa,' viii, p. 623, and Lindley, 'Veg. Kingd.,' p. 315. [200] 'Bull. Soc. Bot. France,' vol. ix, p. 81. [201] Cited in Henfrey, 'Bot. Gazette.' 3, p. 11. [202] Baillon. 'Etudes du Groupe des Euphorbiacées,' p. 205, tab. xv, fig. 19, tab. xix, fig. 31. [203] See also Guillemin, 'Mém. Soc. Nat. Hist. Paris,' I, p. 16; hermaphrodite flowers in _Euphorbia esula_. [204] 'Prod. Flor. N. Holl.,' p. 242. [205] 'Bot. Zeit.,' 1837, p. 335. [206] 'Pflanz, Terat.,' von Moquin-Tandon, p. 208. [207] Schnizlein, loc. cit. [208] 'Bot. Mag.,' tab. 5160, fig. 4. See also 'Gard. Chron.,' 1860, pp. 146, 170; 1861, p. 1092. [209] 'Gard. Chron.,' 1851, p. 499. CHAPTER V. ALTERATIONS IN THE DIRECTION OF ORGANS. The deviations from the ordinary direction of organs partake for the most part more of the nature of variations than of absolute malposition or displacement. It must also be borne in mind how frequently the direction of the leaves, or of the flower, varies according to the stage of development which it has arrived at, to unequal or disproportionate growth of some parts, or to the presence of some impediment either accidental or resulting from the natural growth of the plant. These and other causes tend to alter the direction of parts very materially. =Change in the direction of axile organs, roots, stems, &c.=--The roots frequently exhibit good illustrations of the effect of the causes above mentioned in altering the natural direction. The roots are put out of their course by meeting with any obstacle in their way. Almost the only exception to the rule in accordance with which roots descend under natural circumstances, is that furnished by _Trapa natans_, the roots of which in germination are directed upwards towards the surface of the water. So in _Sechium edule_, the seed of which germinates while still in the fruit, the roots are necessarily, owing to the inverted position of the embryo, directed upwards in the first instance. A downward direction of the stem or branches occurs in many weak-stemmed plants growing upon rocks or walls, or in trees with very long slender branches as in _Salix Babylonica_, and the condition may often be produced artificially as in the weeping ash. The opposite change occurs in what are termed fastigiate varieties, where the branches, in place of assuming more or less of a horizontal direction, become erect and nearly parallel with the main stem as in the Lombardy poplar, which is supposed to be merely a form of the black Italian poplar. M. de Selys-Longchamps has described a similar occurrence in another species of Poplar (_P. virginiana_ Desf.), and amongst a number of seedling plants fastigiate varieties may frequently be found, which may be perpetuated by cuttings or grafts, or sometimes even by seed; hence the origin of fastigiate varieties of elms, oaks, thorns, chestnuts, and other plants which may be met with in the nurseries. Sometimes when the top of the main stem is destroyed by disease or accident, one of the heretofore lateral shoots takes its place, and continues the development of the tree in the original direction. It is often an object with the gardener to restore the symmetry of an injured tree so that its beauty may ultimately not be impaired.[210] Climate appears sometimes to have some influence on the direction of branches, thus Dr. Falconer, as quoted by Darwin,[211] relates that in the hotter parts of India "the English Ribston-pippin apple, a Himalayan oak, a Prunus and a Pyrus all assume a fastigiate or pyramidal habit, and this fact is the more interesting as a Chinese tropical species of _Pyrus_ naturally has this habit of growth. Nevertheless many of the fastigiate varieties seen in gardens have originated in this country by variation of seeds or buds." M. Carrière has also recorded a curious circumstance with reference to the fastigiate variety of the false acacia _Robinia pseudacacia_; he states that if a cutting or a graft be taken from the upper portion of the tree, the fastigiate habit will be reproduced, and the branches will be furrowed and covered with short prickles; but if the plant be multiplied by detaching portions of the root-stock, then instead of getting a pyramidal tree with erect branches, a spreading bushy shrub is produced, with more or less horizontal, cylindrical branches, destitute of prickles.[212] =Eversion of the axis.=--In the case of the fig, the peculiar inflorescence is usually explained on the supposition that the termination of the axis becomes concave, during growth, bearing the true flowers in the hollow thus formed. The cavity in this case would probably be due not to any real process of excavation, but to a disproportionate growth of the outer as contrasted with the central parts of the fig. Some species of _Sempervivum_ have a similar mode of growth, so that ultimately a kind of tube is formed, lined by the leaves, the central and innermost being the youngest. The hip of the Rose may be explained in a similar manner by the greater proportionate growth of the outer as contrasted with the central portions of the apex of the flower-stalk. In cases of median prolification, already referred to, the process is reversed, the central portions then elongate into a shoot and no cavity is formed. A fig observed by Zuccarini (figs. 105, 106) appears to have been formed in a similar manner, the flower-bearing summit of the stalk not being contracted as usual, the flowers projected beyond the orifice of the fig. If this view be correct the case would be one rather of lengthening of the axis than of absolute eversion since it was never inverted. [Illustration: FIG. 105.--Fig showing prolonged inflorescence and projecting flowers.] [Illustration: FIG. 106.--Section of the same.] =Altered direction of leaves.=--The leaves partake more or less of the altered direction of the axis, as in fastigiate elms, but this is not universally the case, for though the stem is bent downwards the leaves may be placed in the opposite direction; thus in some specimens of _Galium Aparine_ growing on the side of a cliff from which there had been a fall of chalk, the stems, owing apparently to the landslip, were pendent, but the leaves were abruptly bent upwards. One of the most singular instances of an inverted direction of the leaves is that presented by a turnip (fig. 107) presented to the Museum of King's College, London, by the late Professor Edward Forbes. The turnip is hollow in the interior and the majority of the leaves springing from its apex instead of ascending into the light and air become bent downwards so as to occupy the cavity, and in such a manner as to bring to mind the position of an inverted embryo in a seed. [Illustration: FIG. 107.--Hollow turnip, showing some of the leaves inverted and occupying the cavity.] =Altered direction of the flower and its parts.=--The changes which take place in the relative position either of the flower as a whole or of its several parts during growth are well known, as also are the relations which some of these movements bear to the process of fertilisation, so that but little space need here be given to the subject beyond what is necessary to point out the frequent changes of direction which necessarily accompany various deviations from the ordinary form and arrangement of parts. In cases where an habitually irregular flower becomes regular, the change in form is frequently associated with an alteration in direction both of the flower as a whole and, to a greater or less extent, of its individual members, for instance of _Gloxinia_, the normal flowers of which are irregular and pendent, there is now in common cultivation a peloriate race in which the flowers are regular in form and erect in position. [Illustration: FIG. 108.--Flower of normal _Gloxinia_.] [Illustration: FIG. 109.--Flower of _Gloxinia_, erect and regular (regular _Peloria_).] Fig. 108 shows the usual irregular form of _Gloxinia_, with which may be contrasted figs. 109, 110 and 111. Fig. 109 shows the regular erect form; fig. 110 the calyx of the same flower; while in fig. 111 are shown the stamens and style of the two plants respectively. In the upper figure the style of the peloriate variety is shown as nearly straight, and the stamens undergo a corresponding change. No doubt the relative fertility and capacity for impregnation of the two varieties is affected in proportion to the change of form. The Gloxinia affords an instance of regular congenital peloria in which the regularity of form and the erect direction are due to an arrest, not of growth, but of development, in consequence of which the changes that ordinarily ensue during the progress of the flower from its juvenile to its fully formed condition do not take place. [Illustration: FIG. 110.--Calyx of erect _Gloxinia_.] [Illustration: FIG. 111.--Stamens of erect regular, and of pendent irregular-flowered _Gloxinia_.] A similar alteration accompanies this form of peloria in other flowers (see Peloria). A change in direction may result also from other circumstances than those just alluded to. Abortion or suppression of organs will induce such an alteration; thus in a flower of _Pelargonium_ now before me three of the five carpels, from some cause or other, are abortive and much smaller than usual, and the style and the beak-like torus are bent downwards towards the stunted carpels instead of being, as they usually are, straight. Amongst orchids, where the pedicel of the flower or the ovary is normally twisted, so that the labellum occupies the anterior or inferior part of the flower, it frequently happens, in cases of peloria and other changes, that the primitive position is retained, the twist does not take place, and so with other resupinate flowers. In Azaleas a curious deflexion of the parts of the flower may occasionally be met with. Fig. 112 shows an instance of this in which the corolla, the stamens and the style were abruptly bent downwards: as young flowers of this singular variety have not been examined it is difficult to form an opinion as to the cause of this variation. In one plant the change occurred in connection with the suppression of all the flowers but one in the cluster, or rather the place of the flowers was occupied by an equal number of leafy shoots. [Illustration: FIG. 112.--Flower of _Azalea_, showing the corolla reflected.] Moquin[213] mentions a flower of _Rosa alpina_ in which two of the petals were erect, while the remaining ones were much larger and expanded horizontally. The same author quotes from M. Desmoulins the case of a species of _Orobanche_, in which a disjunction of the petals constituting the upper lip took place, thus liberating the style and allowing it to assume a vertical direction. [Illustration: FIG. 113.--Flower of _Cuphea miniata_ enlarged, showing protrusion and hypertrophy of an erect placenta, after Morren.] [Illustration: FIG. 114.--Placenta from the flower shown at fig. 113; the ovary is membranous and torn, the placenta, erect and ovuliferous, after Morren.] M. Carrière[214] has described an instance wherein two apples were joined together, a larger and a smaller one; the former was directed away from the centre of the tree as usual, while the smaller one was pointed in exactly the opposite direction. The larger fruit had the customary parchment-like carpels, the smaller was destitute of them. Sometimes the direction assumed by one flower as an abnormal occurrence is the same as that which is proper to an allied species or genus under natural circumstances; thus flowers of the vine (_Vitis_) have been met with in which the petals were spreading like a star (_fleurs avalidouires_), as in the genus _Cissus_.[215] Morren describes a curious condition in some flowers of _Cuphea miniata_, in which the placenta protruded through an orifice in the ovary, and losing the horizontal direction became erect (figs. 113, 114). A similar occurrence happened in _Lobelia erinus_. To this condition the Belgian savant gave the name of gymnaxony.[216] FOOTNOTES: [210] The following details as to the method pursued by Mr. McNab, of the Edinburgh Botanic Garden, may not be uninteresting in this place. They are from the pen of Mr. Anderson, and originally appeared in the 'Gardeners' Chronicle.' "The mode of inducing leaders to proceed from laterals is a matter of comparatively little concern among the generality of deciduous trees, for they are often provided with subsidiary branches around the leader, at an angle of elevation scarcely less perpendicular, but the laterals of all Conifers stand, as nearly as possible, at right angles. Imagine the consternation of most people when the leader of, say, _Picea nobilis_, _P. Nordmanniana_, or _P. Lowii_ is destroyed." In a specimen of the latter plant the leader had been mischievously destroyed, to remedy which Mr. McNab adopted means which Mr. Anderson goes on to describe. "Looking from the leader downward to the first tier of laterals, there appeared to have been a number of adventitious leaf-buds created, owing to the coronal bud being destroyed. These were allowed to plump up unmolested until the return of spring, when every one was scarified or rubbed off but the one nearest the extremity. To assist its development and restrain the action of the numerous laterals, every one was cut back in autumn, and this restraint upon the sap acted so favorably upon the incipient leader as to give it the strength and stamina of the original leader, so that nothing detrimental was evident twelve months after the accident had happened, and only a practical eye could detect that there had been any mishap at all. This beautifully simple process saved the baby tree. "Another example of retrieving lost leaders may be quoted as illustrative of many in similar circumstances. _Pícea Webbiana_ had its leader completely destroyed down to the first tier of laterals. There was no such provision left for inducing leaf-buds as was the case with _P. Lowii_ above referred to. Resort must, therefore, be had to one of the best favoured laterals, but how is it to be coaxed from the horizontal position of a lateral to the perpendicular position of a leader? The uninitiated in these matters, and, in fact, practical gardeners generally, would at once reply, by supporting to a stake with the all-powerful Cuba or bast-matting. But no. A far simpler method than that, namely, by fore-shortening all the laterals of the upper tier but the one selected for a leader. Nature becomes the handmaid of art here; for without the slightest prop the lateral gradually raises itself erect, and takes the place of the lost leader. All that the operator requires to attend to is the amputation of the laterals until this adventitious fellow has gained a supremacy. Singular provision in nature this, which, thanks to the undivided attention of a careful observer, has been fully appreciated and utilized." [211] 'Variation of Animals and Plants,' ii, p. 277. [212] Quoted in 'Gard. Chron.,' 1867, p. 654. [213] Loc. cit., p. 315. [214] 'Rev. Hortic.,' 1868, p. 110. [215] Planchon and Marès, 'Ann. Sc. Nat.,' 5 ser., tom. vi, 1866, p. 228, tab. xii. [216] 'Bull. Acad. Belg.,' xviii, part ii, p. 293. BOOK II. DEVIATIONS FROM THE ORDINARY FORM OF ORGANS. In a morphological point of view the form of the various parts or organs of plants and the changes to which they are subjected during their development are only second in importance to the diversities of arrangement and, indeed, in some cases, do not in any degree hold a second place. Taken together, the arrangement, form, and number of the several parts of the flower, make up what has been termed the symmetry of the flower.[217] Referring to the assumed standard of comparison, see p. 4, it will be seen that in the typically regular flower all the various organs are supposed to be regular in their dimensions and form. At one time it was even supposed that all flowers, no matter how irregular they subsequently became, began by being strictly symmetrical or regular, and that subsequent alterations were produced by inequality of growth or development. The researches of organogenists have, however, dispelled this idea of unvarying primordial regularity, by showing that in many cases flowers are irregular from the very first, that some begin by being irregular, and subsequently become regular, and even in some cases resume their original condition during the course of their development.[218] Under these circumstances an artificial standard of comparison becomes almost an absolute necessity for the time being. Changes of form very generally, but not always, are accompanied with a change in regularity: thus a flower habitually bi-lateral may assume the characters of radiating symmetry and _vice versâ_. Increase or decrease of size very frequently also are co-existent with an alteration in the usual form. In the case of the arrangement of organs it is often difficult or impossible, in the present state of our knowledge, to determine whether a given arrangement is congenital or acquired subsequently to the first development, whether for instance an isolation of parts be due to primordial separation or to a subsequent disunion of originally combined organs, see p. 58. With reference to the changes in the form of organs, however, it is in general more easy to ascertain the proximate cause of the appearance, and thus teratological changes of form may be grouped according as they are due to, 1, arrest of development; 2, undue or excessive development; 3, perverted development; and 4, irregular development; hence the use of the following terms--Stasimorphy, Pleiomorphy, Metamorphy, and Heteromorphy--to include teratological changes really or apparently due to one or other of the causes above mentioned. The classification here adopted is of course to a considerable extent an arbitrary one and subject to correction or modification, as the knowledge of the development of the flowers in the various genera of plants advances. FOOTNOTES: [217] The word symmetry has been used in very different senses by different botanists, sometimes as synonymous with "regularity," at other times to express the assumed typical form of a flower. Payer understands it to be that arrangement of parts which permits of the whole flower being divided vertically into two symmetrical halves (bi-lateral symmetry). Others, again, have applied the term symmetry to the number of the parts of the flower, reserving the terms "regularity" or "irregularity" for the form. It is here used in a general sense to express the plan of the flower, and thus includes the arrangement, form, and number of its component elements. [218] See Baillon, 'Adansonia,' v, 176. PART I. STASIMORPHY.[219] Deviations from the ordinary form of organs arising from stasis or arrest of development are included under this heading. There are many cases in which the forms proper to a juvenile condition of the plant are retained for a much longer period than ordinary, or even throughout the life of the individual growth goes on, but "development" is checked. Such conditions may even be propagated by seed or bud. It is a very general thing for botanists to consider these cases as reversions to a simpler, primitive type, and this may be so; but on the other hand, they may be degenerations from a complex type, or they may have no direct relation to any antecedent condition. Stasimorphic changes affecting principally the relative size of organs--such, for instance, as the non-development of internodes, or the atrophy or suppression of parts will be found mentioned in the sections relating to those subjects. In the present part those alterations which affect the form of organs principally are treated of. FOOTNOTES: [219] [Greek: Stasis-morphôsis]. CHAPTER I. PERSISTENCE OF JUVENILE FORMS. The retention in adult life of a form characteristic of an early stage of development, and therefore usually transient, may be manifested in any of the organs of the plant. As these cases are for the most part treated under separate headings, it is here only necessary to allude to a few, which it is difficult to allocate satisfactorily, while the reader may be referred for other instances of like nature to the sections on Peloria, Atrophy, Suppression, Dimorphy, Substitutions, &c. [Illustration: FIG. 115.--_Juniperus sinensis_. Two forms of leaves on branches of the same shrub.] =Stasimorphy in the leaves of conifers.=--In many conifers the leaves produced in the young state of the plant are different, both in arrangement and form, from those subsequently developed (see pp. 89, 90). But it occasionally happens that the plant continues to form throughout its existence leaves such as are usually produced only in a young state; thus M. Gubler ('Bull. Soc. Bot., Fr.,' vol. viii, 1861, p. 527) describes a plant of _Pinus pinea_ in which the primordial, usually transitory, foliage was permanent, leaves of the ordinary shape not being developed at all. It more often happens that some only of the leaves retain their young form while others assume other shapes, see fig. 115. This happens frequently in the larch and constantly in the Chinese juniper when it has arrived at a considerable age. In _Cupressus funebris_ two forms of leaves may often be found on the same plant, the one representing the juvenile state, the other the more developed condition. What is very singular, is that a cutting taken from the branch with leaves of the young form grows up into a shrub bearing leaves of no other shape, so that an ordinary observer unacquainted with the history of the plant would imagine that he had to deal with two distinct species. This fact is the more interesting when compared with the alternation of generations which takes place among the lower animals. The regular development of all the parts of the flower in a plant habitually producing irregular flowers is referred to under the head of Peloria, but it still remains to consider those examples in which some only of the parts of the flower are affected in this manner.[220] Most of these cases are elsewhere referred to in this volume under the particular form of malformation assumed; but the following case may here be noticed as not coming under any of the previous heads. It is an instance recorded by Professor Babington ('Phytologist,' August, 1853), and in which the pod of _Medicago maculata_, which is usually rolled up like a snail shell and provided with spines, was sickle-shaped and unarmed. FOOTNOTES: [220] See a paper of Professor C. Morren's on "Floral Stesomy" in 'Bull. Acad. Belg.,' t. xix, part ii, p. 519. CHAPTER II. REGULAR PELORIA. [Illustration: FIG. 116.--Regular Peloria, _Delphinium_.] [Illustration: FIG. 117.--Sepal, petal, &c., of regular-flowered _Delphinium_.] [Illustration: FIG. 118--Regular peloria, _Viola_.] [Illustration: FIG. 119--Double Violet, flower regular, petals multiplied, stamens and pistils petaloid.] When an habitually irregular flower becomes regular, it does so in one of two ways; either by the non-development of the irregular portions, or by the formation of irregular parts in increased number, so that the symmetry of the flower is rendered perfect, as in the original peloria of Linnæus, and which may be called irregular peloria, while the former case may be called regular peloria. This latter appearance is therefore congenital, and due to an arrest of development.[221] As the true nature of these cases has not been in all cases recognised (even Moquin places them under the head of deformities--they being less entitled to rank in that class than are the usual flowers), it may be well to cite a few instances taken from various families. In _Delphinium peregrinum_ I have met with perfectly regular flowers having five sepals and five oblong stalked petals, and a similar occurrence has been noted in other species of this genus. Baillon,[222] in referring to these flowers, points out the resemblance that they bear to the double varieties of _Nigella_. In the stellate columbines (_Aquilegia_) of gardens the tubular petals are replaced by flat ones often in increased numbers. In violets both forms of peloria occur, that in which there is an unusual number of spurs, and that in which there are no spurs (var. anectaria). In the more perfect forms of regular peloria occurring in the last-named genus the following changes may be noticed: 1, an alteration in the direction of the flower so that it remains in an erect position, and is not bent downwards as usual; 2, equality of proportion in the sepals and petals; 3, absence of spurs, as also of hairs on the lateral petals; 4, equal stamens whose anthers are sometimes entirely destitute of the prolonged crest which forms so prominent a feature under ordinary circumstances; 5, erect, not curved styles, and the stigmas not prolonged into a beak, but having a more or less capitate form; ovary with three or five cells, ovules normal. These are cases where the change in question is most strongly marked, the bi-lateral is completely replaced by the radiating symmetry. The absence of the usual nectary, and of hairs on the side petals, the alterations in the form of the style, etc., all show how much the process of fertilisation must be altered from that which occurs under ordinary circumstances. In some of the double violets now cultivated in gardens, a similar regularity of proportion in the parts of the flower may be seen combined with the substitution of petals for stamens and pistils, and with the development of an increased number of petal-like organs.[223] Between these cases and the ordinary spurred forms as well as those with an increased number of spurs, many intermediate forms may be met with. That such regularity should occur in this family is not to be wondered at seeing that there is a whole subdivision of the order (_Alsodeiæ_) in which regular flowers are the rule. In cultivated Pelargoniums the central flower of the umbel or "truss" frequently retains its regularity of proportion, so as closely to approximate to the normal condition in the allied genus _Geranium_; this resemblance is rendered greater by the fact that, under such circumstances, the patches of darker colour characteristic of the ordinary flower are completely wanting; the flower is as uniform in colour as in shape. Even the nectary which is adherent to the upper surface of the pedicel in the normal flower disappears--sometimes completely, at other tunes partially. The direction of the stamens and style, and even that of the whole flower, becomes altered from the inclined to the vertical position. In addition to these changes, which are those most commonly met with, the number of the parts of the flower is sometimes augmented, and a tendency to pass from the verticillate to the spiral arrangement manifested. Schlechtendal mentions some flowers of _Tropæolum majus_ in which the flowers were perfectly regular and devoid of spurs[224], while in the double varieties, now commonly grown in greenhouses, the condition of parts is precisely the same as in the double violet before alluded to. Among the _Papilionaceæ_ the Laburnum and others have been noticed to produce occasionally a perfectly regular flower in the centre, or at the extremity of the inflorescence, though the peloria in this flower is usually irregular. In the Gentianaceous genus _Halenia_, _H. heterantha_ is remarkable for the absence of spurs. Amongst _Gesneraceæ_, _Bignoniaceæ_, _Scrophulariaceæ_, and other families of like structure, regular peloria is not uncommon. Fig. 120 represents a case of this kind in _Eccremocarpus scaber_, conjoined, as is frequently the case, with dialysis or separation of the petals.[225] Many of the cultivated Gloxinias also show erect, regular, five stamened flowers, but these are probably cases of irregular peloria. [Illustration: FIG. 120.--Regular peloria, _Eccremocarpus scaber_.] A solitary flower of _Pedicularis sylvatica_ was found by the Marquis of Stafford near Dunrobin Castle in Sutherlandshire, in which the usual ringent form of the corolla was replaced by the form called salver-shaped. There were six stamens, four long and two short. Sir W. Hooker and Mr. Borrer are stated to have found a similar flower in the same locality in 1809.[226] The passage of ligulate to tubular corollas among _Compositæ_ is not of such common occurrence as is the converse change. I owe to Mr. Berkeley the communication of a capitulum of a species of _Bidens_, in which there was a transition from the form of ligulate corollas to those that were deeply divided into three, four, or five oblong lobes. These then were instances of regular peloria. [Illustration: FIG. 121.--Flower of _Cattleya marginata_. Lip replaced by a flat petal.] In _Orchidaceæ_ a similar change is not by any means infrequent; in a few, indeed, a regular flower is the normal character, as in _Dendrobium normale_, _Oncidium heteranthum_, _Thelymitra_, etc. Fig. 121, reduced from a cut in the 'Gardeners' Chronicle,' 1854, p. 804, represents an instance of this kind in _Cattleya marginata_. From the same journal the following account of a case of peloria in _Phalænopsis Schilleriana_ is also cited as a good illustration of this peculiar change. The terminal flower differed entirely from all the others; instead of the peculiar labellum there were three petals all exactly alike, and three sepals also exactly alike; the petals resembled those of the other flowers of the spike, and the upper sepal also; but the two lower sepals had no spots, and were not reflexed as in the ordinary way: thus, these six parts of the flower were all in one plane, and being close together at their edges, made almost a full round flower; the column and pollen-glands were unaffected. Professor Reichenbach also exhibited at the Amsterdam Botanical Congress, of 1865, a flower of _Selenipedium caudatum_ with a flat lip. M. Gris[227] has placed on record some interesting cases of peloria of this kind in _Zingiber zerumbet_; in the more complete forms the androecium or staminal series was composed of six distinct pieces, the three inner of which were fertile, while in the ordinary flower the androecium is composed of two pieces, "a lip" and a fertile stamen. "Is it not a matter of regret," says M. Gris, "to be obliged to call the latter the normal flower?" Under this head may likewise be mentioned those cases in which the normal, or at least the typical symmetry of the flower is restored by the formation of parts usually suppressed; thus Moquin cites an abnormal flower of _Atriplex[228] hortensis_ described by M. Fenzl as having a true calyx within the two bracts that usually alone encircle the stamens. Adanson, also cited by Moquin, found a specimen of _Bocconia_ with a corolla. _Arum maculatum_ has likewise been met with provided with a genuine perianth as in _Acorus_ and other Orontiads. The unusual development of the sexual organs in diclinous flowers has been alluded to under the head of heterogamy, and other cases where the symmetry of the flower is rendered regular, by the development of parts ordinarily suppressed, will be found in the chapters relating to deviations from the usual number of organs. This change, or rather this persistence of a form that is usually transient, is generally accompanied by some other alterations. Change of direction, as has been already mentioned, is one of the most common of these; separation of the petals (_Antirrhinum_, _Verbascum_, &c.), and even their appearance in leaf-like guise, are not infrequent (_Delphinium_, _Antirrhinum_, _Verbascum_, &c.) At other times multiplication or increased number of the whorls of petals takes place, often, but not always, at the expense of the sexual organs of the flower. Perhaps even more frequent is the increased number of parts in the same whorl in cases of regular peloria; thus, in the Pelargoniums before alluded to, the parts of the flower are frequently regulated by the number six instead of five. This form of peloria is most generally met with in flowers that are placed at the end or in the centre of the inflorescence, or in such flowers as occur singly at the end of the flower-stalk, as in _Tropæolum_, _Viola_, &c. It would hence seem as if the freedom from pressure or restriction on one side allowed the flower to develop equally in all directions, and thus to produce regularity of form. It is obvious, from what has been before said, that the process of fertilisation is in many cases interfered with and altered by the change in the conformation or the flower. From overlooking the occasional existence of this form of peloria, new genera have sometimes been formed on insufficient grounds. The genus _Aceranthus_, for instance, consists of species of _Epimedium_ in which the customary spurs are not formed.[229] The occurrence both of regular and irregular peloria on the same plant has frequently been observed in _Linaria_. It has also been remarked that the seedlings raised from these forms are not always constant; thus, the late Mr. Crocker, formerly foreman in the Royal Gardens, Kew, informed me that he fertilised some flowers of a drooping Gloxinia with their own pollen, and that when the seedlings blossomed a large number of them produced the erect regular flowers. From what has been already said it will be seen that regular peloria is closely allied to what Morren called epanody, or a return to the normal condition. The reversion of a monstrous form to the normal one, as, for instance, when the fern-leaved beech reverts to the normal type, was called by the same author epistrophy.[230] The following are the genera in which regular peloria has been most often observed. It must, however, be remarked that in some of the flowers recorded as peloric there is no indication as to which form of peloria the case should be referred to. For other illustrations refer to chapters on Heterogamy, Number, Irregular Peloria, &c. *Delphinium peregrinum! *Nigella damascena! *Aquilegia vulgaris! *Viola odorata! hirta. Epimedium, sp. *Pelargonium zonale! * inquinans! Tropæolum majus! *Wistaria sinensis. Lupinus. *Cytisus Laburnum! Trifolium repens! *Compositæ, gen. pl.! Lonicera Periclymenum! Streptocarpus Rexii. *Digitalis purpurea. *Scrophularia aquatica. *Pentstemon. *Linaria vulgaris! *Antirrhinum majus! Verbascum nigrum! Columnea Schiedeana. Halenia heterantha. Galeobdolon luteum. Prunella vulgaris! Salvia, sp.! Teucrium campanulatum. Betonica alopecuros. Eccremocarpus scaber. Pedicularis sylvatica. Zingiber Zerumbet. Phalænopsis amabilis! Phalænopsis Schilleriana. Habenaria. *Orchis morio. mascula. *Dendrobium, sp. Atriplex, sp. Cattleya Mossiæ! marginata. Calanthe vestita! Oncidium, sp.! Selenipedium caudatum. Arum maculatum. In addition to the references already given, further information on this subject may be gained from consulting the following publications. See also Irregular Peloria. Giraud, 'Bot. Soc. Edinb.,' Dec. 12, 1839, _Antirrhinum_. Dareste, 'Ann. Sc. Nat.,' ser. 2, 1842, xviii, p. 220, _Delphinium_. C. Morren, 'Fuchsia,' p. 90, _Calceolaria_, 'Bull. Acad. Belg.,' xx, part ii, p. 57; and E. Morren, 'Bull. Acad. Belg.,' 2nd ser., xix. p. 224, _Gloxinia_. Richard, 'Mém. Soc. d'hist. nat.,' ii, p. 212, tab. 3. Lindley, 'Journ. Linn. Soc.,' iii, p. 9, _Dendrobium_. Michalet, 'Bull. Soc, Bot. France,' vii, p. 625, _Betonica_. Gubler, 'Bull. Soc. Bot. Fr.,' ix, 81, 'Des anomalies aberrantes et regularisantes.' Reichenbach fil. 'De pollinis orchid. genesi ac structura,' 1852, _Oncidium_. Clos, 'Mém. Acad. Toulouse,' vi, 1862, _Salvia_. Caspary, 'Verhandl. Phys. OEkon. Gesell. Königsberg,' 1860, i, 59, _Columnea_. Bureau, 'Bull. Soc. Bot. Fr.,' 1861, vol. viii, p. 710, _Streptocarpus_. Darwin, 'Variation of Animals and Plants,' ii, pp. 59 and 396. Godron, 'Ex. Bull. Bot. Soc. Fr.,' xiv, p. 165, 'Rev. Bibl.,' _Wistaria_. Marchand, 'Adansonia,' iv, p. 172, _Lonicera_. Baillon, 'Adansonia,' v, p. 177, 'Sur la regularité transitoire de quelques fleurs irreg.,' shows that during the development of some flowers which begin and end by being irregular, there is an intermediate state when all the parts are regular. Helye, 'Revue Horticole,' Sept., 1868, p. 327. In this last paper, published as this sheet is going through the press, the author states that he has raised from seed three generations of plants of _Antirrhinum_ with regular spur-less flowers. The original wild plant was only partially peloric, but all the flowers produced on its descendants were regular. FOOTNOTES: [221] "On the existence of two forms of Peloria," by M. T. Masters. 'Nat. Hist. Review,' April, 1863. [222] Baillon, 'Adansonia,' iv. p. 149. [223] Similar cases are figured in 'Hort. Eystettens. Ic. Pl. Vern.' fol. 4, f. 1, 2. _Viola martia_ multiplici flore. [224] 'Linnæa,' 1837, p. 128. [225] M. Bureau, 'Bull. Soc. Bot. Fr.,' ix, p. 91, describes two genera of _Bignoniaceæ_ in which the flowers are _normally_ regular and six parted. [226] See 'Trans. Linn. Soc.,' vol. x. p. 227. [227] 'Ann. Sc. Nat.,' ser. 4, 1859. tom. xi, p. 264, tab. 3. [228] 'El. Ter. Veg.,' p. 342. [229] Marchand, 'Adansonia,' vol. iv, p. 127. [230] 'Bull. Acad. Belg.,' xvii. p. 17. "Fuchsia," p. 169. PART II. PLEIOMORPHY.[231] Most irregular flowers owe their irregularity to an unequal development of some of their organs as compared with that of others. When such flowers become exceptionally regular they do so either because development does not keep pace with growth, and a regular flower is thus the result of an arrest of the former process (regular peloria), or because the comparatively excessive development, which usually occurs in a few parts is, in exceptional cases manifested by all, hence the flower becomes regular from the increase in number of its irregular elements. These latter cases, then, are due to an excess of development, hence the application of the term pleiomorphy. It must be understood that mere increase in the number of the organs of a flower is not included under this head, but under that of deviations from the ordinary number of parts. FOOTNOTES: [231] [Greek: Pleios-morphôsis]. CHAPTER I. IRREGULAR PELORIA. The term peloria was originally given by Linné to a malformation of _Linaria vulgaris_, with five spurs and five stamens, which was first found in 1742 near Upsal. This was considered so marvellous a circumstance that the term peloria, from the Greek [Greek: pelôr], a prodigy, was applied to it.[232] After a time other irregular flowers were found in like condition, and so the term peloria became applied to all cases wherein, on a plant habitually producing irregular flowers, regular ones were formed. The fact that this regularity might arise from two totally different causes was overlooked, or at least not fully recognised, even by Moquin-Tandon himself. Where a flower retains throughout life the same relative size in its parts that it had when those parts first originated the result is, of course, a regular flower, as happens in violets and other plants. This kind of peloria may for distinction sake be called regular or congenital peloria (see chapter on that subject); but where a flower becomes regular by the increase in number of its irregular portions, as in the _Linaria_ already alluded to, where not only one petal is spurred, but all five of them are furnished with such appendages, and which are the result of an irregular development of those organs, the peloria is evidently not congenital, but occurs at a more or less advanced stage of development. To this latter form of peloria it is proposed to give the distinctive epithet of irregular. Peloria is either complete or incomplete; it is complete when the flower appears perfectly symmetrical, it is incomplete when only a portion of the flower is thus rendered regular. It is very common, for instance, to find violets or Linarias with two or three spurs, and these intermediate stages are very interesting, as they serve to show in what way the irregularity is brought about. In _Antirrhinum_, _Linaria_, &c., intermediate forms show very clearly that it is to the repetition of the form usually assumed by the petals of the lower lip that the condition is due. This is also obvious in peloric flowers of the _Calceolaria_. The perfect peloria of this flower is in general erect, with five regular sepals, a regular corolla contracted at the base and at the apex, but distended in the centre so as to resemble a lady's sleeve, tight at the shoulder and wrist, and puffed in the centre! [Illustration: FIG. 122.--Peloric flower of _Calceolaria_.] Morren[233] describes a form intermediate between the ordinary slipper-shaped corolla and the perfect peloria just described, and which he calls sigmoid peloria. This flower is intermediate in direction between the erect peloria and the ordinary reflected flower. The tube is curved like a swan's neck and is dilated in front into two hollow bosses, such as we see in the lower lip of an ordinary flower; beyond these it is contracted and is prolonged into a slender beak terminating in two hollow teeth, between which is the narrow orifice of the corolla. The colour at the base of the tube inside is as in the perfect peloria; while round the summit of the tube, in both cases, the intensity of colour is greatest on the outside. Now, in a normal flower the deepest colour is within just opposite the orifice of the corolla; this deep colour is also seen outside of the central and most elevated portions of the lower lip. In the peloria the deep colour at the base of the tube represents that which is near the orifice under ordinary circumstances, while the outer patch of colour at the apex corresponds to that formed on the upper surface of the lower lip. On the other hand, in peloric flowers of _Cytisus Laburnum_, _Clitoria Ternatea_, _Trifolium repens_, and other Papilionaceæ, it is the "standard," the form of which is repeated. In the case of peloric aconites[234] the lateral and sometimes the inferior coloured sepals assume the hooded form usually peculiar to the upper sepal only, the number of the petals or nectaries being correspondingly increased. Balsams become peloric by the augmentation in the number of spurs.[235] So when orchids are affected with irregular peloria it is the form of the labellum that is repeated, the accessory lips being sometimes the representatives of stamens, which are usually suppressed in these flowers,[236] but at other times the appearance is due simply to the fact that all three petals assume the form usually confined to the lip, the staminal column being unaffected, except that its direction and relative position with reference to the other parts of the flower is different from ordinary. This was the case in some flowers of _Phalænopsis equestris_ sent to me by Mr. Wentworth Buller. Fig. 123 represents a flower of _Aristolochia caudata_ with two lips, for which I am indebted to Mr. W. H. Baxter. From these cases it is evident that the flowers in question become regular by the repetition of the irregular parts. [Illustration: FIG. 123.--Two-lipped flower of _Aristolochia caudata_.] It is probable that peloria may occur in any habitually irregular flower, and that, if more attention were directed to the subject, illustrations might be obtained from a larger number of natural families than can be done at present. It is, however, necessary to exercise discrimination, and not to attribute to peloria all the cases that at first sight appear to be so referable. Thus, Professor Dickson exhibited at the Botanical Society of Edinburgh, December 13th, 1860, four abnormal flowers of the common Indian cress (_Tropæolum majus_), each presenting a supernumerary spur. On these he remarked that "in _Tropæolum_ the posterior part of the receptacle between the insertion of the petals and that of the stamens is dilated so as to form the spur which is so characteristic in the genus. The position of the spur in a line with the posterior sepal has led many botanists to consider it as a process of that sepal, but the fact of its being situated within the insertion of the petals is conclusive as to its receptacular origin. In the flowers exhibited the supernumerary spur (as if to show its want of connection with any sepal) was placed exactly between a lateral sepal and one of the anterior sepals, sometimes on the one side of the flower and sometimes on the other. These additional spurs were precisely similar to the normal ones, except that they were a little shorter. This abnormality, although at first sight seeming to indicate a pelorian tendency, is no approximation to regularity, from the fact of the extra spur being differently placed, with regard to the sepals, from the normal one." Peloria of this kind, when perfect, is very often associated with other alterations. Change of direction is one of the most common of these; the usually drooping flower becomes erect, the stamens and style also are changed in direction, while, not unfrequently, either the one or the other (most often the stamens) are entirely suppressed. With this suppression an increase in the size of the flower very generally coincides. The number of parts is also frequently increased; thus, in _Antirrhinum majus_ the corolla, when subjected to peloria, is very generally six-parted, and has six stamens. Fusion of one or more flowers is also a common accompaniment of peloria, as in _Digitalis purpurea_, in which plant prolification often adds increased complexity to the flower. It has been stated by Moquin and others that the uppermost flower of an inflorescence is the most subject to peloria; the uppermost flower of _Teucrium campanulatum_, for instance, is very generally regular. In _Calceolaria_ it is the central terminal flower which is usually peloriated; on the other hand, in _Linaria_ and _Antirrhinum_ the lower flowers, or those on the secondary branches, are quite as often affected as the primary ones. Cassini considered that the spur of _Linaria_ was developed from the lower petal rather than from the upper ones, because there is more room on the side of the flower farthest from the stem than on the opposite side. With reference to this point, M. Godron remarks that in habitually irregular flowers the apex of the peduncle is oblique, and hence the flowers are bent downwards or spread horizontally, but if the receptacle be quite flat and level then the flower is regular. The oblique position causes some of the organs to press on others, and hence induces abortion and suppression of some parts and increased growth in others that are not subjected to pressure. In a terminal peloriated flower of aconite, described by this naturalist, the flower was removed so far from the nearest bracts that all its parts had the chance of growing regularly. In ordinary cases M. Godron considers that the compression of the lateral bracts is the cause of the irregularity of the androecium and of the receptacle.[237] It has also been somewhat too generally stated that peloria occurs principally on luxuriant vigorous plants. It seems quite as often to happen in plants characterised by their deficiencies in this respect. On this point M. de Melicoq[238] says, referring to _Linaria vulgaris_ affected with peloria, that on the weakest plants the peloriated flower was at the top of the stem; while in stronger plants, with more numerous flowers and larger foliage, the peloriated flowers were principally to be found in the centre and at the base of the inflorescence, and their pedicels were much longer than usual. Linné, as has been already stated, considered these flowers to be sterile, and only capable of multiplication by division of the root, but Willdenow obtained seeds from the _Linaria_ which reproduced the anomaly when sown in rich soil. Baron Melicoq obtained similar results.[239] Mr. Darwin[240] raised sixteen seedling plants of a peloric _Antirrhinum_, artificially fertilised by its own pollen, all of which were as perfectly peloric as the parent plant. On the other hand, the same observer alludes to the tendency that these peloric plants have to revert to the usual form, as shown by the fact that when the peloric flowers were crossed with pollen from flowers of the ordinary shape, and _vice versâ_, not one of the seedlings, in either case, bore peloric flowers. Hence, says Mr. Darwin, there is in these flowers "a strong latent tendency to become peloric, and there is also a still greater tendency in all peloric plants to reacquire their normal irregular structure." So that there are two opposed latent tendencies in the same plant. A similar remark has been made with reference to malformations in general by other observers. It would be very interesting if some competent naturalist would collect information as to whether any variations in degree of fertility exist in the three forms of flowers in _Linaria_, viz. the ordinary one-spurred form, which is intermediate between the spur-less and the five-spurred form. It must be remembered, however, that in the latter cases the stamens are often deficient. In the _Compositæ_, where there are regular flowers in the disc and irregular ones in the ray, sexual differences, as is well known, accompany the diversities in form. To Mr. Darwin the author is indebted for the communication of some flowers of _Corydalis tuberosa_ (figs. 124, 125), provided with two spurs of nearly equal size. To these flowers allusion is made in the work already quoted[241] in the following terms:--"_Corydalis tuberosa_ properly has one of its two nectaries colourless, destitute of nectar, only half the size of the other, and therefore to a certain extent in a rudimentary state; the pistil is curved towards the perfect nectary, and the hood formed of the inner petals slips off the pistil and stamens in one direction alone, so that when a bee sucks the perfect nectary the stigma and stamens are exposed and rubbed against the insect's body. In several closely allied genera, as in _Dielytra_, there are two perfect nectaries; the pistil is straight, and the hood slips off on either side, according as the bee sucks either nectary." In the flowers of _Corydalis_, which were provided with two perfect nectaries containing nectar, Mr. Darwin considers that there has been a redevelopment of a partially aborted organ, accompanied by a change in the direction of the pistil, which becomes straight, while the hood formed by the petals slips off in either direction, "so that these flowers have acquired the perfect structure, so well adapted for insect agency, of _Dielytra_ and its allies." [Illustration: FIG. 124.--Two-spurred flowers of _Corydalis_.] [Illustration: FIG. 125.--Section through two-spurred flowers of _Corydalis_, Magnified.] Peloria, then, is especially interesting physiologically as well as morphologically; it is also of value in a systematic point of view, as showing how closely the deviations from the ordinary form of one plant represent the ordinary condition of another; thus, the peloric Calceolarias resemble the flowers of _Fabiana_, and De Candolle,[242] comparing the peloric flowers of _Scrophulariaceæ_ with those of _Solanaceæ_, concluded that the former natural order was only an habitual alteration from the type of the latter. Peloric flowers of _Papilionaceæ_ in this way are indistinguishable from those of _Rosaceæ_. In like manner we may trace an analogy between the normal one-spurred _Delphinium_ and the five-spurred columbine (_Aquilegia_), an analogy strengthened by such a case as that of the five-spurred flower of _Delphinium elatum_ described by Godron.[243] The _Corydalis_, before referred to, is another illustration of the same fact, the structure being the same as in _Dielytra_, &c. The ordinary irregular flowers may possibly be degenerated descendants of a more completely organized ancestor, and some of the cases of peloria may therefore be instances of reversion; some ancient _Linaria_ may, perhaps, have had all its petals spur-shaped, and the cases of irregular peloria now found may be reversions to that original form. When both regular and irregular forms of peloria occur on the same plant, as they frequently do in _Linaria_, the one may be perhaps considered as a reversion to a very early condition, the other to a later state, when all the petals were irregularly formed. But before we can assert the truth of this surmise we must have better evidence as to what the original condition really was than we have at present. The proximate cause of irregular peloria has been considered to be excess of nourishment, but evidence as to this point is very conflicting. Willdenow states that "radices peloriæ, solo sterili plantatæ, degenerant in Linariam," ('Sp. Plant.,' iii, p. 254); but this opinion is counterbalanced by that of others, while the frequent existence of both forms on the same plant, at the same time, seems to negative the supposition of any direct effect from external circumstances. The following are the plants in which irregular peloria has been most often observed: Aconitum Napellus. Delphinium elatum! Corydalis tuberosa. *Viola odorata! hirta. Impatiens Balsamina. Clitoria Ternatea. Cytisus Laburnum! Trifolium repens! Lupinus polyphyllus! *Gloxinia, var. cult.! *Linaria vulgaris! spuria. Elatine. triphylla. æruginea. triornithophora. pilosa. chalepensis. cymbalaria! purpurea! decumbens. Pelisseriana. origanifolia. Digitalis orientalis. * purpurea! Calceolaria crenatiflora. rugosa. * var. cult.! Chelone barbata. *Antirrhinum majus! Rhinanthus crista galli. Pedicularis sylvatica. Pedicularis euphrasioides. Scrophularia aquatica! Sesamum indicum. Lamium. Mentha. Sideritis. Nepeta diffusa. Galeopsis Ladanum. Tetrahit. Galeobdolon luteum. Teucrium campanulatum! Plectranthus fruticosus. Cleonia lusitanica. Dracocephalum austriacum. Phlomis fruticosa! Vitex incisa. Aristolochia, sp.! Ophrys aranifera! Orchis simia. pyramidalis! latifolia! morio! papilionacea. mascula. latiflora. conopsea. Habenaria bifolia. Corallorhiza innata. Aceras anthropophora. Cattleya Moasiæ! Phalænopsis equestris! Pogonia ophioglossoides! The literature of peloria is very extensive. The following are the principal papers, not already mentioned, which relate to the subject, arranged under the genera, placing those first which are most subject to this anomaly (see also Regular Peloria). _Linaria_.--Adanson, 'Fam. Plant.,' t. i, p. 110. Jussien, 'Gen. Plant.,' p. 120. Poiret, 'Encycl. Method, Suppl.,' t. iii, Jaeger, 'Missbilld. der Gewachs.,' pp. 94, 97, and 313. Cassini, 'Op. Phytol.,' t. ii, p. 331. Ratzebourg, 'Animadv. ad pelor. spectand.,' 1825. Turpin. 'Ic. Veget.,' tab. xx, f. 16. Curtis, 'Flor. Londin.,' i, 118. Hopkirk, 'Flora Anom.,' pl. vii, figs. 1, 2, 3. Haller, 'Act. Helvet.,' 2, p. 25, t. iv. De Candolle, 'Flore Franc.,' t. iii, p. 583. Sowerby, 'Engl. Bot.,' iv, 260, ed. Syme, tab. 963. Chavannes, 'Mon. Antirrhin.' Delavaud, 'Bull. Soc. Bot. France,' 1858, p. 689; id., 1860, p. 175. Heufler, 'Linnæa,' xvii, tab. ii. Weber, 'Verhandl. des Nat. Hist. Vereins. f. d. Rh. Preuss.,' 1850, tab. i, figs. 1-8. 'Verh. Nat. Hist. Ver. Rh. Preus.,' 1849, vol. vi, p. 290, tab. xiii.--_Antirrhinum_, Clos, 'Mém. Acad. Toulous.,' vi, 1862. Chavannes, 'Mon. Antirrh.,' p. 62. Fresenius, 'Mus. Senkenb.,' ii, t. iv, fig. 10. 'Bot. Soc. Edinb.,' 1851, July 10.--_Calceolaria_, Chamisso, 'Linnæa,' t. vii, p. 206. Guillemin, 'Archiv. Bot.,' t. ii, p. 1 et 136. Schlechtendal, 'Linnæa,' xii, p. 686. Ernst Meyer, 'Linnæa,' xvi, 26, tab. iii. Morren, 'Bull. Acad. Belg.,' t. xv, n. 7, et t. xviii, p. 583. 'Gard. Chron.,' 1850, p. 389; ibid., 1866, p. 612.--_Viola_, Leers, 'Flor. Herborn.,' p. 145. De Candolle, 'Organ. Veget.,' t. i, p. 519, pl. xlv. Forbes, 'Proc. Linn. Soc.,' June 6, 1848, p. 382. Hildebrand, 'Bot. Zeit.,' 1862, vol. xx, tab. viii.--_Orchidaceæ_, His, 'Jourl. Phys.,' 65, p. 241. Wydler, 'Arch. Bot.,' t. ii, p. 310, tab. xvi. R. Brown, 'Obs. organ. Orchid.,' p. 698. A. Richard, 'Mém. soc. d'hist. nat.,' t. i, p. 212. Greville, 'Flora Edinens.,' p. 87 (_Corallorhiza_). Curtis, 'Flora Londinensis,' t. lxxxii. Morren, C., 'Bull. Acad. Roy. Belg.,' t. xix, part ii, p. 171. Clos, 'Mém. Acad. Sc. Toulous.,' 5 ser., vol. iii. Caspary, 'Schrift. K. Gesellsch. Königsberg,' 1860, i, 59. Masters, 'Jourl. Linn. Soc.,' vol. viii, p. 208 (_Ophrys_, _Pogonia_). Duchartre, 'Bull. Soc. Bot. Fr.,' vol. vii, 1860, p. 26, _Cattleya_. Cramer, 'Bildungsabweich.'--_Limosella_, Baillon, 'Adansonia,' i, p. 305. (Flower normally irregular, becoming regular "à force d'irregularité.")--_Chelone_, Chamisso, 'Linnæa,' vii, p. 206,--_Clitoria_, Bonavia, 'Gard. Chron.,' 1868, p. 1013. In this latter communication, published as this sheet is passing through the press, the author gives an interesting account of the transitional stages between the ordinary papilionaceous condition and the regular form which is like that of a Rosaceous plant. The peloric form is stated to be transmitted by seed. For other references see Moq.-Tandon, 'El. Terat. Veget.,' p. 186. Hallier, 'Phytopathol.,' p. 151. FOOTNOTES: [232] 'Amoen. Acad.,' i, p. 55, t. iii (1744):--The following note refers to Linné's notion that these forms were due to hybridization. It is extracted from Gmelin's edition of the 'Systema Naturæ,' 1791, p. 931. "_Linariæ_ proles hybrida, ejusdemque qualitatis et constans, radicibus infinite sese multiplicans charactere fructificationis diversissima, corolla regulari, quinque-corniculata, pentandra, ut genus proprium absolute constitueret et distinctissimum, nisi fructus frequentissime abortiret. Naturæ prodigium. Ita quidem a Linné. Verisimilor autem videtur ea opinio, quæ peloriam pro peculiari degeneratione monstrosa floris habet, in quam inclinare hoc genus (Linaria) præ aliis, similis a forma deflexio in aliis speciebus, e.g. _spurio Elatine_, _cymbalaria_, observata, ... Merk., 'Goett. gel. Anz.,' 1774, n. 121. Linck, 'Annal. Naturg.,' i, p. 32." [233] 'Bull. Acad. Belg.,' xviii, part i, p. 591. Lobelia, p. 137. [234] See also Seringe, 'Esquisse d'une Monogr. du genre _Aconitum_,' p. 124. [235] Schlotterbec, 'Act. Helvet.,' t. ii, pl. i, Roeper. Balsam, p. 10, note. [236] Masters. "Peloria, &c., _Ophrys aranifera_," 'Journ. Linn. Soc.,' viii, p. 207. [237] Godron, "Mém. sur les Fumarieès à fl. irreg.," 'Ann. Sc. Nat.,' sér. 5, vol. ii, tab. xvii, p. 280. [238] 'Bull. Soc. Bot. France,' vol. v, 1858, p. 701. [239] 'Bull. Soc. Bot. France,' vol. vi, 1859, p. 717. [240] 'Variation of Anim. and Plants,' ii, p. 70. [241] Loc. cit., p. 59. [242] 'Théor. Elém.,' ed. 2, p. 266. [243] Cited in 'Bull. Soc. Bot. France,' vol. xiii (Rev. Bibl.), p. 81. PART III. METAMORPHY. Much of the objection with which Goethe's famous essay on the 'Metamorphosis of Plants' was met on its publication may be traced to a misapprehension of the sense in which Goethe employed the word. As used by him, it had nearly the same signification as now applied to the word development by organogenists. It does not necessarily imply that there has been a change in any particular organ, but rather that there has been, to some extent, a change in the plan of construction, in accordance with which a deviation from the customary form results. The particular organ was never anything else than what it is; it has not been metamorphosed in the ordinary sense of the word; for instance, in a double flower, where the stamens are, as it is said, changed or metamorphosed into petals, no absolute change really has taken place--the petal was never a stamen, although it occupies the position of the latter, and may be considered a substitute for it. The term metamorphosis, then, really implies an alteration in the organizing force, taking effect at a very early period of the life of the flower, at or before the period when the primitive aggregation of cells, of which it is at that time composed, becomes separated or "differentiated" into the several parts of the flower. In other words, the "development" of the flower pursues a different course from what is usual. In the preceding sections the effects of arrest and of excess in this process have been partly treated of; other deviations arising from similar causes will be mentioned elsewhere, but, under the present heading, are specially included cases not of merely diminished or increased, but of perverted development; the natural process is here not necessarily checked or enhanced, but it is changed. Hence, in the present work, the term metamorphy is employed to distinguish cases where the ordinary course of development has been perverted or changed. As it is applied solely for teratological purposes, the ordinary acceptation of the term, as nearly synonymous with "development," is not interfered with. In order to avoid other possible misapprehensions, the terms retrograde and progressive metamorphosis employed by Goethe are not herein used, their place being, to a great extent, supplied by the more intelligible expressions arrest or excess of development.[244] FOOTNOTES: [244] See Goethe, 'Versuch. der Metam. der Pflanzen,' 1790. English translation by Emily M. Cox, in Seemann's 'Journal of Botany,' vol. i, 1863, p. 327. For a brief sketch of the origin and progress of the theory of vegetable morphology, prior to the publications of Wolff, Linné, and Goethe, as well as for an attempt to show what share each of these authors had in the establishment of the doctrine, the reader is referred to an article in the 'Brit. and For. Medico-Chirurgical Review,' January, 1862, entitled "Vegetable Morphology: its History and Present Condition," by Maxwell T. Masters. CHAPTER I. PHYLLODY. This condition, wherein true leaves are substituted for some other organs,[245] must be distinguished from Virescence, q. v., in which the parts affected have simply the green colour of leaves, without their form or structure. The appearance of perfect leaves, in place of other organs, is frequently looked on as due to retrograde metamorphosis, or to an arrest of development. But this is not strictly correct; for instance, suppose a petal, which is very generally merely the sheath of a leaf, with the addition of colouring matter, to be replaced by a perfect leaf, one in which all three constituent parts, sheath, stalk, and blade, are present, it surely can hardly be said that there has been any retrogression or arrest of development in the formation of a complete in place of an incomplete organ. The term retrograde here is used in a purely theoretical sense, and cannot be held to imply any actual degradation. Morphologically, as has been stated, the case is one of advance rather than the reverse, and hence the assignment of instances of this nature to a perversion of development, rather than to a diminution or to an exaltation of that process, seems most consistent with truth. The affected organs have really undergone no actual change, simply the direction of the organising force has been altered at a very early state, so that the usual differentiation of parts has not taken place. [Illustration: FIG. 126.--'Rose plantain,' _Plantago media var._, spike contracted; bracts leafy.] =Phyllody of the bracts.=--As bracts are very generally imperfect organs, so their replacement by perfect leaves is not attributable to arrest of development or retrograde metamorphosis, but the reverse. The bracts of some species of _Plantago_[246] are very subject to this change. Thus, in the rose plantain of gardens, _P. media_ (fig. 126), the bracts are leafy and the axis depressed or not elongated, so that it is surmounted by a rosette of small leafy organs. A similar condition of the bracts, unattended with arrest of growth in the axis, is common in _P. major_ (fig. 127) and in _P. lanceolata_ (see p. 108). It also occurs in the bracts of _Corydalis solida_, _Amorpha fruticosa_, _Ajuga reptans_, _Parthenium inodorum_, _Centaurea Jacea_, in the involucral bracts of the dandelion, the daisy, and many other composites. In the 'Gardeners Chronicle,' 1852, p. 579, is figured a dahlia in which the bracts of the involucre and the scales of the receptacle had all assumed the form, texture, and venation of leaves.[247] [Illustration: FIG. 127.--Leaf-like bracts in _Plantago major_.] [Illustration: FIG. 128.--Dahlia. Scales of receptacle leafy.] In _Umbelliferæ_ the substitution of leaves for involucral bracts is not infrequent. It has been observed among other plants in _Angelica Razoulzii_, _Carum carui_, _Daucus Carota_, &c. The scales of the hop (_Humulus Lupulus_) not infrequently manifest this change, as do also the bracts of many amentaceous plants, _e.g._ in the male catkins of the walnut, the female catkins of the alder,[248] of some willows,[249] &c. The bracts of some _Euphorbiaceæ_, as _E. pusilla_, _E. Lathyris_, _E. Cyparissias_, have been observed to undergo a similar alteration.[250] Amongst monocotyledons an analogous change occurs not unfrequently, as in some commelynaceous plants, _e.g._ _Tradescantia_, in _Musa_, &c. The spathe of _Arum maculatum_ is sometimes represented by a stalked leaf similar to that which occurs, under ordinary circumstances, in _Spathiphyllum_, but in which genus the spadix is more or less adherent to the leaf-like spathe.[251] In _Schoenus cephalotes_ a similar exaggerated development of the bracts is figured by Rottboell.[252] =Phyllody in inflorescence of Conifers.=--This demands passing notice by reason of the interest attaching to the morphological construction of these plants. The elongation of the axis which occurs in the female cones has been already alluded to under the head of prolification of the inflorescence. This change is frequently associated with a more or less foliaceous condition of the bracts, which, indeed, may be seen to be serially continuous, both above and below, with the ordinary leaves. The scales, too, become notched and bipartite, and show, between the lobes, the rudiment of a bud, which in a further stage becomes developed into a shoot bearing leaves. Such a change has been described by Parlatore in _Abies Brunoniana_, and examples may frequently be met with in the larch (_Larix europæa_), and specially in _Cryptomeria japonica_.[253] The scales of the male catkins of conifers likewise occasionally assume the appearance of leaves; this may be seen in monstrous catkins of _Araucaria_, as also in _Podocarpeæ_ and _Cupressineæ_ (Eichler). =Phyllody of the calyx.=--Sepals under ordinary circumstances are so like leaves, that it is not wonderful that they are often replaced by those organs.[254] A singular instance of this has been mentioned as occurring in _Cakile maritima_, wherein the sepals were found by M. Fournier to be pinnatifid like the ordinary leaves of the plant.[255] The sepals of _Ranunculaceæ_ and _Rosaceæ_, for example, _Rosa_, _Geum_, are particularly liable to this change. [Illustration: FIG. 129.--Flower of rose, sepals replaced by five perfect leaves; axis prolonged through the flower in the form of a leafy branch.] In a species of _Geranium_ recently examined the sepals presented themselves in the form of three-lobed leaflets; so in fuchsias and in _Epilobium hirsutum_ the sepals occasionally are not distinguishable from ordinary leaves (fig. 130). In roses, the change in question is a very frequent accompaniment of prolification (fig. 129). In the peach also this replacement of the sepals is sometimes carried to such an extent, that five perfect, bistipulate leaves occur in the place of the calyx, but when this is the case it usually happens that the pistil is abortive. [Illustration: FIG. 130.--Fuchsia, with one of the sepals leaf-like.] De Candolle[256] figures a curious instance wherein the pappus of _Podospermum laciniatum_ was replaced by five linear, foliaceous lobes. A similar change has been noticed in other composites, as in _Tragopogon pratense_. Engelmann mentions as subject to this hypertrophy of the pappus, as it may be termed, _Scorzonera octangularis_ and _Senecio vulgaris_. Wigand has observed a similar transformation in a species of _Centranthus_ (_Valerianaceæ_). In some cases the phyllody of the sepals has a special interest, as bearing on the question whether what is termed calyx-tube is or is not a portion of the calyx, and whether the sepals are modifications of the blade or of the sheath of the leaf. Thus in the primrose the phyllodic sepals seem to show clearly that the sepals are in that plant of a laminar nature (fig. 131). The so-called calyx-tube of roses is elsewhere alluded to. The leaf-like organs sometimes seen at the apex of a cucumber would seem to support the view that there was really a calyx-tube in _Cucurbitaceæ_ adherent to the carpels. It is also shown in the cut, fig. 132, borrowed from the 'Gardeners' Chronicle,' 1859, p. 654. [Illustration: FIG. 131.--Primrose. Calyx of foliaceous segments.] [Illustration: FIG. 132.--Leafy calyx of melon.] Under ordinary circumstances, the sepals may be considered as the representatives of the sheath of the leaf (cataphyllary) or of the blade (euphyllary), the arrangement of the veins being different in the two cases; thus, in the vagina or sheath, there are generally several large veins of about equal size, either convergent towards the apex, or divergent; on the other hand, in the blade, there is usually but one central vein, the midrib, larger than the rest, and the smaller veins come off at a less acute angle, and are more reticulated.[257] Now, when phyllomorphy occurs in sepals which ordinarily are vaginal, it is obvious that the case is one, not merely of increased relative growth, but also of the appearance or development of an organ habitually suppressed; on the other hand, when phyllomorphy occurs in sepals which usually are laminar in form and nervation, the case is one of unusual growth or hypertrophy, and not of the development of an organ habitually suppressed, so that the amount of change is greater in the former than in the latter instance. Under normal circumstances it will be found that laminar venation is most common in gamosepalous and vaginal venation in polysepalous calyces. And the same holds good in cases where the calyx is abnormally leafy. The complete leaf development shows itself more frequently among the monosepalous plants than in the polysepalous ones, as shown even in the subjoined list of species. This statement would be more fully verified were it possible to state the frequency with which the condition occurred in _individual plants_, when it would be found that phyllody of the calyx occurs much more often in individual gamosepalous plants than in polysepalous ones. Phyllody of the calyx has been most often observed in the following plants: Ranunculus acris! Delphinium Ajacis. Caltha palustris. Anemone Pulsatilla. sylvestris! nemorosa! hortensis! coronaria! *Papaver orientale. Escholtzia crocea. Cakile maritima. Diplotaxis tenuifolia. Thlaspi arvense. Cheiranthus Cheiri. incanus. Sinapis arvensis. Brassica oleracea! Peltaria alliacea. *Sisymbrium officinale. Caryophyllaceæ,[258] sp. pl. Geranium, sp.! *Fuchsia, var. hort.! Epilobium hirsutum! Cucurbita Pepo! *Rosa, var. hort.! Potentilla nepalensis. Fragaria sp. Geum rivale. Amygdalus communis. Persica vulgaris. Cerasus! Pyrus Malus. Daucus Carota. Athamanta Cervaria. *Trifolium repens! Centranthus macrosiphon. Tragopogon pratense. orientale. Scorzonera octangularis. Hypochæris radicata. *Senecio vulgaris! Podospermum laciniatum. Cirsium arvense. Carduus heterophyllus tataricus. Campanula, sp. Convolvulus sepium. *Primula officinalis, var. cult! acaulis. elatior. Gentiana campestris. *Petunia violacea! Lycium europæum. Laurus Sassafras. Tulipa Gesneriana. Convallaria maialis. Colchicum autumnale! (virescent?) Consult also Turpin, 'Atlas de Goethe,' t. iv, f. 12, _Lycium_. Engelmann, 'De Anthol.,' § 35, p. 31. This author figures phyllodic sepals in _Senecio vulgaris_, tab. v, figs. 24-26; _Campanula_, tab. iii, f. 15, 16; _Athamanta cervaria_, tab. v, f. 14. Lindley, 'Elements of Botany,' 1847, pp. 64, 73, &c. 'Gard. Chron.,' 1858, p. 685; 1859, p. 654, _Cucurbita_. Petunnikoff, 'Bull. Soc. Imp. Moscow,' 1862, _Cirsium_. Braun, 'Rejuvenescence,' Ray Society's Transl. See succeeding paragraphs. =Phyllody of the corolla.=--The petals also are frequently replaced by leaves, though in many of the recorded instances the change has been one of colour only; these latter are strictly cases of virescence. M. Seringe[259] speaks of a flower of _Peltaria alliacea_ in which the calyx was petal-like, while the corolla was leafy as if there had been transposition of the two organs, a very rare, if not unparalleled, instance. In a flower of _Campanula Medium_, provided, as is often the case, with a double corolla, the outer corolla was slit down on one side, the edges of the cleft being leafy. [Illustration: FIG. 133.--Sepals and petals to leaves. _Geranium_.] The frondescent petals are very often completely disjoined, as in _Verbascum nigrum_, and _Lonicera Periclymenum_, in which, moreover, median prolification generally coexists. In the case of _Tropæolum majus_, the ordinary leaves of which are peltate and orbicular, the petals when frondescent have not the peltate arrangement, but are spathulate, and provided with very long, narrow stalks, so that, in some cases, they are, more properly speaking, enlarged virescent petals than true leaves; in other instances, however, the arrangement of the veins is more like that of the true leaves than that of the petals. As might be expected, frondescence of the petals is frequently accompanied by other changes of a similar nature in other parts of the flower, and sometimes by the abortion of the sexual organs. Thus, in _Actæa spicata_, as observed by Fresenius, the petals were replaced by true petiolate, palminerved, lobed leaves, the stamens and pistils being abortive. In _Ranunculus_ the leaves that appear in the place of the petals have no scale at their base, and in _Tropæolum_ the calyx (or receptacle) is free from the usual spur. The absolute frequency of this occurrence seems to be greatest in those flowers which are normally polypetalous. The petals of these flowers, as a general rule, are more like the leaf-sheaths than the leaf-blades as to their venation, hence it would seem that the phyllomorphic condition in these petals is a manifestation of a greater degree of organizing force than that which occurs in those cases where the petals are normally present in the form of contracted blades or laminæ. (See the remarks in the preceding section.) Frondescence of the petals has been observed most frequently in the following cases; some, perhaps, were cases merely of virescence, q. v.; see also under Chloranthy, Prolification. Ranunculus repens! Delphinium Ajacis. crassicaule. Aquilegia vulgaris. Actæa spicata. *Brassica oleracea! Diplotaxis muralis. Hesperis matronalis. Thlaspi bursa pastoris. Sisymbrium tenuifolium. Turritis glabra. Raphanus sativus. Peltaria alliacea. Alyssum incanum. Erysimum Barbarea. officinale! cheiranthoides. Cheiranthus Cheiri. *Dictamnus Fraxinella! Lychnis sylvestris. dioica! Alsine media. Cerastium vulgatum! triviale. Reseda lutea. Phyteuma. Malva sylvestris. *Tropæolum majus! Geranium, sp.! Triumfetta, sp.! Epilobium hirsutum! OEnothera striata. Rubus, sp. *Rosa, var. cult.! *Trifolium repens! Spiræa oblongifolia. Amygdalus communis. *Rosa! Cerasus vulgaris! Persica vulgaris! Potentilla nepalensis. Geum rivale. Daucus Carota! Heracleum Sphondylium. Torilis Anthriscus. Echinophora maritima. Campanula rapunculoides. glomerata. Phyteuma spicatum. Calendula officinalis. Cirsium tricephalodes. Senecio vulgaris. Scabiosa columbaria. agrestis. Lonicera xylosteum. Periclymenum. Gentiana Amarella. Gilia glomeriflora. *Symphytum officinale. Petunia violacea! Verbascum, sp. Antirrhinum majus! Stachys sylvatica. *Anagallis phoenicea? Primula sinensis! Polemonium coeruleum. See Moquin-Tandon, 'El. Terat. Veg.,' p. 203. Engelmann, 'De Anthol.,' § 38 _et seq._; tab. ii, figs. 8-14, _Gilia_; tab. v, 23-26, _Senecio_; tab. v, f. 1-13, _Torilis_; tab. iv, f. 3, _Erysimum_. 'Bull. Soc. Bot. Fr.,' vol. ii, 1855, p. 479, _Primula sinensis_. Giraud, 'Edinb. Phil. Magazine,' 1839, _Antirrhinum_. Jaeger, 'Act. Acad. Cæs. Nat. Cur.,' vol. xiii, 2, p. 1, tab. xli, _Tropæolum_. Bischoff, 'Lehrbuch,' 11, 2, p. 27, _note_, _Tropæolum_. Fresenius, 'Mus. Senkenb.,' ii, 35, tab. 4, fig. 5, _Actæa_. See also succeeding paragraphs and sections in Chloranthy, Virescence, &c. =Phyllody of the stamens= happens less frequently than the corresponding condition in the neighbouring organs. The structure of the anther is so much removed from that of the leaf, that the change of the stamen from its ordinary condition to that of a leaf must be regarded as indicating a greater degree of perverted development than that which occurs in those cases where less highly differentiated organs, such as the sepals, petals, and pistils, are thus altered.[260] In all cases it is desirable to ascertain, if possible, what parts of the stamen are thus transformed. In some Petunias the filaments are unchanged, but in place of the anther is a small lamina, representing precisely the blade of an ordinary leaf. Sometimes the connective only is replaced by a leaf. One of the most interesting cases of this kind that has fallen under the writer's observation was in _Euphorbia geniculata_, in which, in addition to other changes mentioned under prolification of the inflorescence, some of the stamens were partly frondescent, half the anther being perfect, the other half leaf-like. Another filament bore just above the usual joint three leaflets, two lateral ones, somewhat conduplicate, and a third central one, half anther, half leaflet. [Illustration: FIG. 134.--Flower of a _Petunia_, opened to show the stamens partially replaced by stalked leaves.] In the case of frondescent flowers of _Tropæolum majus_ the stamens are usually absent or atrophied, but in other instances the filament is present as usual, representing the stalk of the leaf, and surmounted by a small lamina, but this latter, in place of being nearly flat, is pinched up in the centre from back to front, and surmounted by a two-lobed anther, so that the general appearance of the whole structure is that of a central anther, supported at the base on each side by two concave leaf-lobes, or it might be compared with a three-lobed leaf, the terminal lobe represented by the anther. In _Jatropha Pohliana_, Müll. (_Adenorophium luxurians_, Pohl.), a singular condition has been observed by M. Müller (Argov.). In this flower the anther, in place of being represented by the flat blade of a single leaf, had the appearance as if two such blades were present and coherent one with the other by their midribs, along their upper or inner surfaces, which were directed towards the centre of the flower (fig. 136), thus resembling the cases of adhesion of leaves by their surfaces already referred to (p. 33). In other cases, in the same plant, the anther appeared as if formed by two collateral leaves, the faces looking towards the circumference of the flower, and their margins so folded together as to represent an open anther lobe (fig. 135). These cases are apparently due, not to the formation and adhesion of two leaves, but rather to the exuberant development of one leaf into two blades.[261] The bearings of these and other similar malformations on the morphology of the anther are alluded to under the head of petalody of the anther. [Illustration: FIG. 135.--Phylloid anther of _Jatropha_, after Müller (Arg.).] [Illustration: FIG. 136.--Leaf-like anther of _Jatropha Pohliana_, after Müller.] Phyllody of the stamens has been most often observed in the following plants: Anemone nemorosa. coronaria. Delphinium crassicaule. Nymphæa dentata. Tropæolum majus! Dictamnus albus. *Trifolium repens! Torilis anthriscus. Heracleum Sphondylium. Daucus Carota Epilobium hirsutum! *Rosa, var. cult.! Lonicera Periclymenum. Anagallis arvensis. Primula sinensis! Petunia, var. cult. Jatropha Pohliana. Euphorbia goniculata. In addition to the foregoing there are very numerous instances of similar substitution in chloranthic flowers. In the above list only those cases are given wherein the leafy change is confined to the stamens, or, at least, to a few only of the other parts of the flower. =Phyllody of the pistils.=[262]--This is of more common occurrence than is the corresponding change in the case of the stamens. It is of interest, as it sometimes serves to illustrate the morphological nature of the pistil. Of this the double-flowering cherry is a well-known illustration, the pistil being here represented by two small foliar laminæ, whose midribs are prolonged with a short style, terminated by an imperfect stigma. It is usually the basal portion of the pistil, the ovary, which is thus specially affected, the margins being also often disunited so as to expose the ovules. These latter organs may be absent or they may themselves be the subjects of foliaceous development. Moquin[263] relates having found in the neighbourhood of Montpellier a flower of a tulip the ovary of which was represented by true leaves, which bore on their margins the ovules, and thus presented a striking analogy with the carpels of those Sterculias, like _S. platanifolia_, which are foliaceous in texture and open very early in the course of their development. A similar occurrence has also been frequently noticed in the Columbine and also in _Cruciferæ_ and _Umbelliferæ_. M. Germain de St. Pierre mentions an instance wherein the carpels of _Salix Babylonica_ were converted into two leaves, provided with stipules. All the flowers of the catkins were similarly changed, so that it became permanent, and resembled a branch. [Illustration: FIG. 137.--Rose, in which the axial portion of the flower was elongated and the carpels were more or less replaced by leaves.] Substitutions of this kind form the green "eyes" or centres of certain varieties of _Ranunculus_ and _Anemone_. In proliferous roses, or in cases where the central axis of the flower is prolonged, it frequently happens that the pistils are more or less replaced by leaves. Fig. 137, from a specimen of Dr. Bell Salter's, given in the 'Gardeners' Chronicle,' shows the passage, from below upwards, of the ordinary carpels to perfect leaves; the so-called calyx-tube being completely deficient and the ovaries entirely superior. Like most similar specimens, this one bears out the notion that what is called the calyx-tube in roses is really an expansion and dilatation of the top of the flower-stalk. [Illustration: FIG. 138.--Cucumber with leaf attached.] Fig. 138, for which I am indebted to Mr. S. J. Salter, represents a very singular conformation in the cucumber, described by that gentleman in 'Henfrey's Botanical Gazette,' i, p. 208, and considered by him to be due to the foliaceous condition of one of the three carpels of which the fruit is composed. The portion near the peduncle was binary, while the distal extremity of the fruit was ternary. The main difficulties attending the acceptance of this explanation reside in the peculiar reversed position of the leaf, and in the fact that the fruit of the _Cucurbitaceæ_ is probably of axial nature, the dilated and succulent end of the peduncle adhering to and usually concealing the carpels; in some cases, however, these latter project beyond the axial portion, leaving no doubt as to the true nature of the structure in these particular instances. Admitting the axial nature of the fruit, it might be supposed that in Mr. Salter's cucumber an adventitious leaf had been given off from the axis, but even on that supposition the reversed position offers a difficulty, and there still remains to be explained the fact that the proximal part of the fruit was binary in its constitution, the distal end ternary. M. Norman[264] mentions a case wherein the carpels of _Anchusa ochroleuca_ were replaced by two leaves; from this he draws the inference that the pistil of borages and labiates is really composed of two leaves, placed fore and aft, the margins of the leaves being congenitally fused. This tallies well with the account given of the development of these plants by Payer, Germain de St. Pierre, and others. In an Indian species of _Triumfetta_, not only were the petals virescent, but the ovary also was much enlarged, and in some flowers it was divided half way down into five lanceolate leaves (fig. 139), the sepals and stamens being in their normal condition. In the preceding instances the foliaceous condition has pervaded the entire pistil, or at any rate the basal portion or ovary, and it may be noticed that the ovary is thus shown to consist in some cases of the sheath of the leaf, as in _Aquilegia_; in other cases of the blade, as in _Cerasus_, _Daucus_, &c. [Illustration: FIG. 139.--Flower of _Triumfetta_, sp., carpels represented by five leaves.] There are cases, however, in which a part only of the pistillary structure thus becomes foliaceous. Linnæus, 'Prolepsis,' § 9, mentions some flowers of _Carduus heterophyllus_ and _C. tataricus_ in which the style had grown into two green leaflets, and in which the calyx and corolla were also leaf-like. A very singular instance is recorded by Baillon,[265] wherein the pistil of _Trifolium repens_ consisted of three carpels, either separate, or combined so as to form a one-celled ovary with three parietal, pluri-ovulate placentæ; the ovary in these flowers was formed of the basal vaginiform part of the leaf; the three styles were formed by the petioles, while the stigmas were represented by trifoliolate leaves. The back of the leaf in these cases is usually directed away from the centre of the flower. When this change occurs it is commonly attended by an increased number of parts, as in the trefoil just mentioned, or in the double cherry, where usually two foliaceous carpels may be met with, and sometimes more. The change is also of interest when it affects such orders as the _Umbelliferæ_, which have their ovaries inferior under ordinary circumstances; but when these organs assume a leafy condition they become superior also, _i.e._ they are detached from the calyx. As regards the position of the ovules in these foliaceous pistils, they may be placed, as in _Aquilegia_, _Delphinium_, &c., on the edges of the carpel or on the surface, as in some flowers of _Ranunculus repens_ and _R. Ficaria_. A similar position of the ovules is recorded in the case of the vine (_Vitis_), where the pistil consisted of leaves bearing the ovules on their inner surface.[266] The supposed causes of this and other similar malformations are alluded to under the head of chloranthy, but it may be here remarked that semi-double flowers, fertilised by the pollen of similar flowers, are said to produce flowers with a centre of small green leaves, this central tuft resulting from the expansion and frondescence of the pistils. As this condition rarely occurs without corresponding changes in other parts of the flower, further remarks on this subject will be found in the chapter relating to Chloranthy. Phyllody of the pistil has been most frequently recorded in the following plants: Pæonia officinalis. Ranunculus repens! *Aquilegia vulgaris! Delphinium elatum. crassicaule. Ajacis. amænum. Nymphæa dentata. Sinapis arvensis! Diplotaxis tenuifolia. *Brassica oleracea! *Sisymbrium officinale! Dianthus. sp Reseda Phyteuma. Triumfetta, sp.! Lychnis dioica. Cerastium, sp.! *Dictamnus Fraxinella! Cerasus avium. vulgaris! *Rosa, var. cult.! *Daucus Carota! Heracleum, sp. Epilobium hirsutum! Lathyrus latifolius. *Trifolium repens! hybridum. Melilotus, sp. Medicago, sp. Lonicera Periclymenum. Carduus heterophyllus. tataricus. Scrophularia aquatica. Symphytum officinale. Anchusa ochroleuca. paniculata. *Primula sinensis! Salix babylonica. Hyacinthus, sp. Tulipa, sp. Some of the above are probably cases of mere virescence rather than of phyllody. For further illustrations, references to authorities, &c., see under Chloranthy, Virescence, Prolification, &c. =Phyllody of the ovules.=--Pending the settlement of the existing differences of opinion with reference to the morphological nature of the ovule and its component parts, much interest attaches to the malformations to which they are occasionally subject. Considered purely in a teratological point of view, it seems clear that the ovular coats are usually, if not always, of foliar nature, while the central nucleus is an axial organ; but if this be so there still remains the question whether the leafy coats of the ovule are processes of the carpel itself, or distinct independent formations, like the scales of a leaf-bud; as to this latter point, the evidence is at present very conflicting. Prof. Al. Braun, who has devoted much attention to the subject, describes and figures ovules of _Nigella_ and _Adonis_, wherein the outer coat of the ovule was converted into a leafy, lobed mass, like the ordinary leaves, and these he considers to be a portion, not of the carpel, but of the ovular bud; he, however, hesitates to pronounce an opinion on the nature of the pedicel of the ovule. In _Primulaceæ_, wherein ovular changes are very common, the leafy coat of the ovule would seem, from the nature of the placenta, to be independent of the carpel. Morren, who studied the changes in the ovules of _Primula sinensis_, applied the term lepyrophylly ([Greek: lepyron], a scale) to the foliaceous condition of the testa in this plant. Unger[267] describes a series of malformations in _Primula sinensis_, consisting chiefly of reversions of the part of the flower to leaves. The carpels were entirely absent in this case, and the place of the free central placenta was occupied by a circle of leaves, sometimes bearing imperfect ovules on their edges. An instance of a similar kind has been described by A. de Candolle.[268] In these flowers the placenta seemed to be composed of several funiculi soldered together, and bearing imperfect ovules. In other cases no traces of ovules are visible, but the funiculi are in a foliaceous condition. Moquin also alludes to a case of the same nature in _Cortusa Mathioli_, in which the funiculi bore little rounded leaves. Brongniart has described some malformations of _Primula sinensis_ in which the ovules were transformed wholly or partially into small leaves with three to five lobes.[269] Dr. Marchand[270] mentions similar changes in _Anagallis arvensis_ and _Lonicera Periclymenum_. Cramer[271] figures ovules of _Primula sinensis_ in the form of stalked leaves, often becoming infolded at the margins, and giving origin to a small nucleus on their inner surface. M. Tassi[272] records an instance in _Symphytum officinale_ wherein the ovules were replaced by two small linear leaves arising entirely from the axis, and not from the carpels. In most of the foregoing illustrations the foliar portion of the ovule must have been independent of the carpel; this independence is less manifest, though probably as real in the cases now to be mentioned. In _Sinapis_ and in _Brassica oleracea_ foliaceous ovules may occasionally be seen, attached to the placenta by long stalks. No trace of the nucleus is visible in these specimens. [Illustration: FIG. 140.--_Sinapis_, replum and ovules; the dotted line shows the position of the carpels.] Griffith, in alluding to a similar case in _Sinapis_,[273] describes the ovules as foliaceous, and having their backs turned away from the axis, the raphe being next to the axis and representing the midrib the funicle corresponding to the petiole. The outer tegument of the ovule, according to Griffith, is a leaf united along its margins, but always more or less open at its apex. No inversion can, therefore, really take place in anatropous ovules, but the blade of the leaf is bent back on the funicle, with which its margins also cohere. Caspary, in an elaborate paper on phyllomorphy occurring in _Trifolium repens_, figures foliaceous ovules springing from the edge of an open, leafy carpel. The nucleus of the ovule, in these cases, appears to originate as a little bud from the surface of the leafy ovule (figs. 141, 142). [Illustration: FIG. 141.--Leafy ovules, &c., _Trifolium repens_.] In a species of _Triumfetta_ (see p. 260), of which I examined dried specimens, the ovary was open and partly foliaceous; it bore on its infolded margins ten erect leaflets, representing so many ovules; each leaflet was conduplicate, the back being turned towards the placenta. [Illustration: FIG. 142.--Leafy ovules of _Trifolium repens_, showing formation of nucleus, &c. After Caspary.] On the other hand, there are cases in which the leafy coat of the ovule, in place of being a distinct organ, seems to originate from the margin of the carpellary leaf itself--to be, as it were, a lobule or small process of the carpel, and not an absolutely new growth. Thus, Planchon[274], from an examination of some monstrous flowers of _Drosera intermedia_, was led to the inference that the ovules are analogous to hairs on the margins of the leaves. This acute botanist was enabled to trace all the gradations between the simple cup formed by the confluence of four glanduliferous hairs and the concave leaf and the perfect ovule. Brongniart[275] records ovules of _Delphinium elatum_ existing in the form of marginal lobes of the carpellary leaf itself; so that each ovule corresponds to a lobe or large tooth of this leaf, the funiculus, as well as the raphe, being formed by the median nerve of the lateral lobe. M. Clos[276] mentions a similar instance in _Aquilegia Skinneri_; and another is figured in Lindley's 'Elements of Botany,' p. 88, f. 180. [Illustration: FIG. 143.--Portion of an open foliaceous carpel of _Delphinium_, with ovules on the lobules.] Cramer[277], from an examination of several ovular malformations, as well as from the investigation of the mode of evolution of the ovules, is led to a similar conclusion with reference to the production of ovules from the modified lobes of the carpellary leaf. Figs. 143-145, copied from Cramer, show how the nucleus of the ovule is formed as a new growth from the surface of the lobes of the leaf in _Delphinium elatum_. [Illustration: FIG. 144.--Section through marginal lobe of carpel (_Delphinium_), showing the nucleus (_n_).] [Illustration: FIG. 145.--Section through marginal lobe of carpel, showing nucleus and tegument (_Delphinium_).] [Illustration: FIG. 146.--1. Placenta of _Dianthus_, bearing ovules and carpels. 2. One of the ovaries separated.] [Illustration: FIG. 147.--Ovules of _Dianthus_ passing into carpels.] One of the most singular instances of ovular malformation in record is that cited by the Rev. M. J. Berkeley, in the 'Gardener's Chronicle,' September 28th, 1850, p. 612. The plant was a carnation, and its placenta bore, not only ovules, but also carpels (fig. 146), the latter originating in a perverted development of the former, so that many intermediate stages could be traced between the ordinary ovule and the ovary (fig. 147, 1, _a_, 2, _b_). Some of these carpels, thus derived from the ovules, themselves bore secondary ovules on a marginal placenta, as shown in the sections at _c_, _d_, _e_. Could such a change occur in the animal kingdom, there would be the unfertilised ovum converted into an ovary, and this again bearing Graafian vesicles! In Mr. Berkeley's carnation the change was not so great, seeing that the nucleus of the ovule was not developed, and sufficient evidence has been above given as to the foliar nature of the primine, while for a leaf to be folded up so as to form a carpel is an ordinary occurrence. It is worthy of remark that in these foliaceous ovules there is never more than one coat, the secondine and other integuments do not make their appearance in these cases, and that very generally the change in question accompanies a similar foliaceous condition in the carpel, the margins of which are more or less disunited. Prof. A. Braun remarks that up to this date no such change has been observed in the ovules of Monocotyledons. =Changes in the nucleus of the ovule.=--The preceding remarks have had reference especially to the ovular coats, but it is desirable also to allude to certain points connected with the nucleus. Very frequently, when the coat of the ovule is phylloid, as before described, the nucleus is altogether wanting, though sometimes it is present as a small cellular papilla; very rarely is it to be found in its perfect state. Occasionally the nucleus is present in the guise of a small elongated branch. Wigand cites ovular buds in every stage of progress into a branch, sometimes even bearing indications of anthers. Wydler has observed a similar occurrence in ovules of _Alliaria officinalis_, and Schimper has described and figured specimens of _Nigella damascena_ in which the outer coats of the ovule were but little changed, while the nucleus was replaced by a leafy shoot. On one of the leaves of this latter was found an imperfect ovule--an ovule on an ovule! Fig. 148 shows a floret of a species of _Gaillardia_, in which the ovule was replaced by a leafy shoot which had made its way through a chink in the ovary. In this specimen, however, there was no evidence to show whether the shoot in question was a perverted development of the nucleus, or whether it was wholly independent of the ovule. [Illustration: FIG. 148.--Floret of _Gaillardia_, showing leafy shoot occupying the place of the ovule.] From this occasional elongation of the nucleus, as well as from the foliar nature of the ovular coats, Prof. Alex. Braun arrives at the conclusion that the ovule is to be looked on as a bud, the ovular coatings, so often variable in number, representing the scales of the bud, the nucleus corresponding to the end of the axis or growing point. Griffith had previously expressed the same opinion from his observations on malformed ovules of _Sinapis_ and _Lonicera_, while Caspary's conclusions from the foliaceous ovules of _Trifolum repens_ are somewhat similar. The latter observer considers that the funiculus, with the integuments, is the equivalent of a leaflet, the petiolule or midrib of which answers to the funiculus, and its hollow expansion to the integument. The nucleus itself is considered to be a new formation analogous to a shoot. M. van Tieghem's conclusion[278] from the examination, of flowers of _Tropæolum majus_, in which the ovules were replaced by perfect peltate leaves, is that the ovules are foliar productions springing, not directly from a prolonged floral axis, as in _Primulaceæ_, but from branches of the axis arising from the axils of the carpellary leaves. Phyllody of the ovules has been met with most often in the following species: *Aquilegia vulgaris! Skinneri. Delphinium crassicaule. elatum. dictyocarpum. Ajacis. Nigella damascena. Adonis autumnalis. Cheiranthus Cheiri! Nasturtium, sp. Sisymbrium officinale! Brassica napus! * olcracea! *Alliaria officinalis! Sinapis arvensis! Turritis, sp. Thlaspi arvense. Erucastrum Pollichii. Stellaria media. *Reseda lutea. Drosera intermedia. Agrostemma Githago. Stellaria media. Triumfetta, sp.! Tropæolum majus! Dictamnus albus. Fraxinella! Caram carui Pastinaca sativa. Torilis anthriscus. Thysselinum palustre. Epilobium palustre. Rosa, sp. Fragaria alpina. *Trifolium repens! Medicago maculata. Desmodium canadense. Melilotus macrorhiza. Lonicera, sp. Gaillardia! Crepis, sp. Phyteuma odorata. Symphytum Zeyheri. * officinale. Stachys sylvatica. Anagallia arvensis. phoenicea. Lysimachia ephemerum. *Primula sinensis! Auricula. prænitens. Gilia glomeruliflora. Rumex arifolius. scutatus. Salix capræa. The following list of publications relating to ovular malformations is copied from A. Braun, 'Ueber Polyembryonie und Keimung von Cælobogyne' (Appendix),[279] to which are also added some others not alluded to by that author and not specially referred to in the preceding pages: Jaeger, 'Missbilld. d. Gewächse,' p. 78, 79, f. 47. Roeper, 'Enum. Euphorb.,' 1824. p. 45, _Delphinium_.--Schimper, 'Flora,' 1829, pp. 437-8, et 'Mag. fur Pharmacie de Geiger,' 1829-30, pl. iv-vi, text wanting, _Primula_, _Reseda_, _Cheiranthus_.--Engelmann, 'De Antholysi,' 1832.--Valentin, 'Act. Acad. Nat. Cur.,' 1839, p. 225, _Lysimachia_.--Unger, 'Act. Acad. Nat. Cur.,' xxii, 11, 1850, p. 543, t. 5 B, _Primula_.--'Flora (B. Z.)', 1842, p. 369, t. ii, _Trifolium_.--Brongniart, 'Ann. Sc. Nat.,' 1834, ii, p. 308; also 'Archives Mus. d'Hist. Nat.,' 1844, t. iv, p. 43, pl. iv, v, _Primula_.--Reissek, 'Linnæa,' xvii, 1843, _Alliaria_.--Wydler, 'Denkshrift. d. Regensb. Bot. Gesell.,' 1855, iv, s. 77, t. vii, _Alliaria_.--Wigand. 'Grundlegung der Pflanzen Teratol.,' 1850, p. 39, _Turritis_.--Wigand, 'Bot. Untersuchungen,' 1853, p. 23, _Rosa_, _Turritis_, _Crepis_.--Germain de St. Pierre, 'L'lnstitut,' 1853, n. 1051, p. 351.--Rossmann, "Entwicklung der Eiknospen aus dem Fruchtblatte," &c., 'Flora,' 1855, pp. 647 and 705.--Dareste, 'Ann. Sc. Nat.,' 1842, p. 220, _Delphinium_.--Fresenius, 'Mus. Senkenb.,' ii, p. 39, t. iv, f. 9, _Primula_.--Schultz, 'Flora o. d. Bot. Zeit.,' 1834, xvii, p. 121, _Nasturtium_.--Seringe and Heyland, 'Bull. Bot.,' 1-7, _Diplotaxis_.--Clos, 'Mem. Acad. Toulouse,' vi, 1862, _Delphinium_.--Morren, C., 'Bull. Acad. Belg.,' xix, part ii, p. 519, _Primula_.--Caspary, 'Schrift. d. Physik. OEk. Gesell. zu Königsberg,' band ii, p. 51, tabs. ii, iii. Fleischer, 'Ueber Missbildungen Verschiedener Cultur Pflanzen.,' &c., Esslingen, 1862. Cramer, 'Bildungsabweich,' p. 68, &c. &c., _Trifolium._--Moquin-Tandon, 'El. Terat. Veg.,' p. 206, _Cortusa_.--Guillard, 'Bull. Soc. Bot. Fr.,' 1857, vol. iv, p. 761, _Stellaria_.--Moelkenboer, 'Tijdschrift v. Natuurl. Geschied.,' 1843, p. 355, t. vi, vii, _Primula_.--Van Tieghem, 'Bull. Soc. Bot. Fr.,' 1865, p, 411, _Tropæolum_. =Phyllody in accessory organs.=--In addition to the ordinary organs of the plant, what are termed the accessory organs, such as hairs, spines, &c., sometimes become foliaceous. It is not to be wondered at that spines, when they represent the framework of a leaf, become sometimes clothed with cellular tissue, and thus become indeed true leaves. This happens occasionally in _Berberis;_ a similar thing occurs in the stipules of some _Leguminosæ_; the scales of some begonias; the tendrils of _Bignonia_, _Cobæa_, &c. The presence of two small green laminæ on the outer side of the two posterior stamens in _Antirrhinum majus_ has also been met with. The adventitious organs appeared as if they were developments from the thalamus--a kind of foliaceous disc, in fact. [Illustration: FIG. 149.--Leafy petal of _Epilobium_.] [Illustration: FIG. 150.--Chloranthy, &c. _Epilobium hirsutum_.] =Chloranthy.=--The term phyllomorphy is applied to the individual parts of the flower which assume the form and appearance of leaves. By chloranthy it is to be understood that all, or the great majority of the organs of the flower assume these conditions.[280] In chloranthy, as here defined, there is no unusual number of buds, as there is in prolification, but the appearance of the flower-bud is so changed as to make it resemble more closely a leaf-bud than a flower-bud. There is not necessarily any increase in the number, or any alteration in the position of the buds, but the form and appearance of the latter differ from what is usual. Chloranthy, then, is a more complete form of frondescence. Owing to the vagueness with which the word has been applied by various authors, it becomes very difficult to ascertain whether the recorded instances of chloranthy were really illustrations of what is here meant by that term, or whether they were cases of mere virescence (green colour, without other perceptible change), or of prolification (formation of adventitious buds). It is, therefore, quite possible that some of the instances to be now mentioned were not strictly cases of chloranthy. [Illustration: FIG. 151.--_a._ Open leafy carpel of "green rose," with two deformed ovules. _b._ Ovule separate. _c._ Primine removed. _d._ Secondine and nucleus, with the bulbous end that projects through the micropyle.] Seringe[281] has described a malformation in _Diplotaxis tenuifolia_ in which all the floral organs were replaced by sixteen distinct leaflets which had preserved their proper relative position. The _Cruciferæ_, of which family the last-named plant is a member, are particularly liable to this malformation, as also are the _Rosaceæ_, as will be seen from the following illustrations. Roses indeed often exhibit alterations of this kind as the commencement of prolification. There is also in cultivation a rose[282] called the green rose, "Rose bengale à fleurs vertes," in which all the parts of the flower are represented by leaves. One of the most remarkable features in this plant is, that the carpels have often two ovules on their margins. Now, Payer, in his "Organogénie," has shown that at a certain period of the development of the ordinary rose flower the ovary contains two collateral ovules, of which one becomes in process of time suppressed.[283] _Geum coccineum_ has been found by Wigand with its flowers in this condition.[284] Lindley[285] figures a very interesting illustration in _Potentilla nepalensis_, in which some of the flowers have their component parts leafy, in others the receptacle lengthens, till in extreme cases the whole of the floral apparatus is represented by a branch bearing a rosette of leaves. A particular variety of the Alpine strawberry is also described as occasionally subject to this transformation. In these flowers the calyx remains normal, while all the other parts of the flower, even to the coating of the ovule, assume a leaf-like condition.[286] Among _Leguminosæ_ a partial leafy condition (frondescence), or a more complete degree of the same change, (chloranthy) is not infrequent, particularly in _Trifolium repens_. In this species the changes are so common, so various and important, that they may be alluded to in some little detail. M. Germain de Saint Pierre,[287] in commenting on the frequency with which the flowers of this plant are more or less frondescent, remarks that although all the flowers on one plant may be affected, they are all changed in the same manner, but on different specimens different degrees of transformation are found. In all the corolla and stamens are comparatively little removed from the ordinary form, the calyx and pistil, however, have a particular tendency to assume a foliar condition. The author just cited arranges the malformations of this plant under three heads, as follows: 1. Calyx-teeth larger than usual, sometimes dentate at the margin; petals more or less regular and disposed to run away from the papilionaceous form; filaments free; anthers normal; carpel transformed into a true leaf with a long stalk provided at the base, with two stipules, terminal leaflet, solitary, green, with no trace of ovules. Sometimes a second carpellary leaf, similar to the first, is formed; in other cases the central axis of the flower is occasionally prolonged into a head of young flowers--median prolification. In some few instances the calyx is not at all altered, but the carpellary leaf is trifoliolate, or even quinquefoliolate, the corolla being then absent. The heads of flowers in this first form have the aspect of little tufts of leaves. 2. Each of the teeth of the calyx is represented by a long stalk, terminated by a single articulated leaflet, the bi-labiate form of the calyx is still recognisable; the two upper petals are united, the three lower separate; the tube of the calyx is not deformed and seems to be formed of the petioles of the sepals united by their stipules. In this second class of cases the corolla is papilionaceous, the filaments free, the carpellary leaf on a long stalk provided with stipules, its blade more or less like the usual carpel, with its margins disunited or more commonly united with the ovules in the interior, sometimes represented by a foliaceous, dentate primine only. In one case the carpel was closed above, gaping below, where it gave origin to several leaflets, the lower ones oval, dentate, like ordinary leaflets, the upper ones merely lanceolate, leafy lobes, representing the primine reduced to a foliaceous condition. Inflorescence--a head with leafy flowers on long stalks, which are longer at the circumference than in the centre. 3. Calyx-teeth lance-shaped, acuminate; corolla more or less regular, arrested in its development and scarcely exceeding the tube of the calyx within which it is crumpled up; stamens but little changed; carpellary leaf on a short stalk, not exceeding the calyx tube, but the ovarian portion very long, and provided with abortive ovules. These three groups will be found to include most of the forms under which frondescence of the clover blossoms occurs, but there are, of course, intermediate forms not readily to be grouped under either of the above heads. Such are the cases brought under the notice of the British Association at Birmingham in 1849 by Mr. R. Austen, in some of which the petals and stamens even were represented by leaves. Although, on the whole, chloranthy is most frequent in the families already alluded to, yet it is by no means confined to them, as the examples now to be given amply show. Specimens of _Nymphæa Lotus_ have been seen in which all the parts of the flower, even to the stigmas, were leafy, while the ovules were entirely wanting. Planchon[288] figures and describes a flower of _Drosera intermedia_ that had passed into a chloranthic condition, excepting the calyx, which was unchanged; the petals, like the valves of the ovary, were provided with stipules, and were circinate in vernation. M. A. Viaud-Grand-Marais[289] records an interesting example of chloranthy, in which the sepals, petals, pistils, and ovules of _Anagallis arvensis_ were all foliaceous. Similar changes have not unfrequently been met with in _Dictamnus Fraxinella_. M. Germain de Saint Pierre has also recorded the following deviations in the flowers of _Rumex arifolius_ and _R. scutatus_; in these specimens the calyx was normal, the petals large, foliaceous, shaped like the stem-leaves, the stamens were absent, the three carpels fused into a triangular leafy pod, as long again as the perianth, the stigmas normal or wanting, the ovule represented by a thick funicle, terminated by a foliaceous appendage analogous to the primine.[290] In grasses it frequently happens that the flowers are replaced by leaf-buds; this condition is alluded to elsewhere under the head of viviparous grasses, but in this place may be mentioned a less degree of change, and which seems to have been a genuine case of chloranthy in _Glyceria fluitans_, the spikelet of which, as observed by Wigand,[291] consisted below of the ordinary unchanged glumes, but the remaining paleæ as well as the lodicles and stamens were represented by ligulate leaves. The plant, it is stated, was affected by a parasitic fungus. On the other hand, General Munro, in his valuable monograph of the _Bambusaceæ_,[292] refers to an illustration in which "the lowest glumes generally, and the lowest paleæ occasionally, had the appearance of miniature leaves, with vaginæ, ligules and cilia, enveloping, however, perfect fertile spiculæ; as progress is made towards the top of the spike, the ligule first, then the cilia, and finally, the leaf-like extension disappears, and the uppermost glumes assume the ordinary shape and form of those organs." =General remarks on chloranthy and frondescence.=--Moquin remarks with justice that the position of the flowers on the axis is of importance with reference to the existence of chloranthy. Terminal flowers are more subject to it than lateral ones, and if the latter, by accident, become terminal, they seem peculiarly liable to assume a foliaceous condition. Kirschleger says, that in _Rubus_ there are two sorts of chloranthy, according as the anomaly affects the ordinary flowering branches, or the leafy shoots of the year, the summits of which, instead of developing in the customary manner, terminate each in one vast and long inflorescence, very loose and indeterminate, and with axillary flowers.[293] On the whole, taking in consideration cases of partial frondescence, as well as those in which most of the parts of the flower are affected, phyllody would seem to be most common in the petals and carpels, least so in the case of the stamens and sepals. It is more common among polysepalous and polypetalous plants than in those in which the sepals or petals are united together. The causes assigned for these phenomena are chiefly those of a nature to debilitate or injure the plant; thus it has been frequently observed to follow the puncture of an insect. M. Guillard[294] gives an instance in _Stellaria media_ where the condition appeared to be due to the attacks of an insect _Thrips fasciata_. Still more commonly it arises from the attacks of parasitic fungi, _e.g._ _Uredo candida_, in Crucifers, &c. In other cases it has been observed when the plants have been growing in very damp places, or in very wet seasons, or in the shade, or where the plant has been much trampled on. This happens frequently with _Trifolium repens_. The frequency with which the change is encountered in this particular species is very remarkable; it is difficult to see why one species should be so much more subject to the kind of change than another of nearly identical conformation. It might at first be supposed that the same causes that bring about the complete substitution of leaf-buds for flower-buds (see Heterotaxy) would operate also in the partial substitution of leaves for other parts of the flower, but it will be seen that the inducing cause, whether similar or not in the two cases respectively, acts at different times; in the one case, it is not brought into play until the rudiments of the flower are already formed, whereas in the other the influence is exerted prior to the formation of the flower. So that while the formation of leaf-buds in place of flower-buds may be and generally is due to an excess of nutrition, inducing over activity of the vegetative organs, the production of phyllomorphic or chloranthic flowers may be owing rather to a perversion of development arising from injury or from some debilitating agency. The discrepancies in the assigned causes for the conditions above mentioned may, therefore, in great measure, be attributed to the different periods at which the causes in question operate. The following list may serve as a guide to the plants most frequently the subjects of chloranthy, but reference should also be made to preceding and subsequent sections, and to that relating to prolification of the inflorescence. Aquilegia vulgaris. Chelidonium majus. Corydalis aurea. Nymphæa Lotus! *Brassica oleracea! Bunias. Hesperis matronalis. *Sinapis arvensis! Sisymbrium officinale. Erucastrum canariense. Diplotaxis tenuifolia. Lychnis dioica! Cerastium glomeratum! triviale. Stellaria media. Poterium polygamum. Torilis anthriscus. Seseli, sp. Selinum caruifolium. Epilobium hirsutum! Begonia fuchsioides. Gomphia, sp. Scabiosa Columbaria. Dipsacus fullonum. Matricaria Parthenium. Calendula officinalis. Campanula pyramidalis. Reseda odorata! Vitis vinifera. Dictamnus Fraxinella! Triumfetta, sp.! *Tropæolum majus! Rhamnus Frangula. *Trifolium repens! Lupinus, sp. Rosa diversifolia! Potentilla nepalensis. argentea. Fragaria vesca! Geum rivale. Rubus fruticosus. cæsius. Saxifraga foliosa. Verbascum phlomoides. Scrophularia nodosa. aquatica! *Primula sinensis! Lysimachia Ephemerum. Anagallis arvensis. Webbiana. Nicotiana rustica. Anchusa ochroleuca. Myosotis cæspitosa. Stachys sylvatica. Gilia capitata. Euphorbia segetalis. Rumex arifolius. scutatus. Juncus lampocarpus. uliginosus. In addition to the publications before cited the following may be named as containing valuable information on the subject of this chapter. Jæger, 'Missbild. Gewächs.,' 1814, p. 83, _Trifolium repens_. For other accounts of similar malformations in the same plant, see Schmitz, 'Linnæa,' xv, p. 268. Unger, 'Flora' (B. Z.) xxv, p. 369. Caspary, 'Schrift. der. Physik. ökon. Gesellsch. zu Königsberg,' 2, 1861, p. 51, tabs. ii, iii. Fleischer, 'Missbilld. verschied. Cult. Pflanz.,' 1862, p. 55, &c., t. v, vii, &c. For _Primula_ see Brongniart, 'Ann. Sc. Nat.,' ser. 2, t. i, p. 308. A. P. and Alph. De Candolle in 'Neue Denkschrift.' Morren, C., 'Bull. Acad. Roy. Belg.,' xix, part 2, p. 539. Molkenboer, 'Tijdschr. voor Natuurl. Geschied.,' 1843, p. 355, tabs. vi, vii. Marchand, 'Adansonia,' iv, p. 167 and p. 159. _Anagallis_, p. 171, _Lonicera_, p. 83, _Juncus_. For other plants see Fresenius, 'Mus. Senk.,' 2, p. 35, &c. Norman, 'Ann. Sc. Nat.,' ser. 4, 1858, vol. ix, p. 220. Christ, 'Flora' (B. Z.) 1867, p. 376, tabs. v, vi, _Stachys_. Cramer, 'Bildungsabweich.,' p. 26, &c. Baillon, 'Adansonia,' ii, p. 300. Moquin-Tandon, 'El. Ter. Veg.,' p. 230. Schauer's translation, p. 220. Hallier, 'Phytopathologie,' p. 160. FOOTNOTES: [245] Engelmann makes use of the word frondescence in the same cases. 'De Anthol.,' p. 32, § 38, while Morren adopts the term Phyllomorphy, 'Lobelia,' p. 95. [246] See Schlechtendal, 'Bot. Zeit.,' vol. xv, 1857, p. 873; also Marchand, 'Adansonia,' iv, p. 156. [247] For instances of similar changes in _Composites_, see De Candolle, 'Prod.,' t. vi, p. 571, _Centaurea Jacea phyllocephala_. Clos, 'Ann. Sc. Nat.,' ser. iii, tom. xvi, 1851, p. 41. 'Science Gossip,' 1865, p. 104, &c. [248] Kickx, 'Bull. Acad. Belg.,' t. xviii, part 2, p. 288. [249] Weber, 'Verhandl. Nat. Hist. Vereins. f. Preuss.,' &c., 1860, p. 381. [250] Weber, loc. cit. [251] Sauter, 'Flora v. Bot. Zeit.,' 1831, p. 11. [252] 'Descr. et Icon. Plant.' tab. 20. [253] For references see p. 115; see also to Eichler, 'Excurs. Morpholog. de format. flor. Gymnosperm.,' in "Mart. Flor. Brasil," abstracted in English in 'Natural History Review,' April, 1864. [254] "Calyx tunc plane non differt a foliis proxime ipsi præcedentibus." Wolff, 'Theor. Gener.,' § 114. Linn., 'Proleps.,' § 6. Goethe, 'Versuch.,' §§ 31-38. [255] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 697. [256] 'Organ. Véget.,' t. i, p. 492, pl. xxxii, f. 6. [257] This distinction between laminar and vaginal venation is well seen in cases like _Mussaenda_, _Calycophyllum_, or _Dipterocarpus_, where the enlarged calycine segment has a strictly vaginal arrangement of its veins, very different from that which occurs in the true leaf-blades. These are cases, therefore, where the sheath of the leaf is unusually enlarged, and are not to be referred, as is often done, to metamorphosis of one or more sepals to perfect leaves. Prolified roses, cherries, &c., furnish frequently parallel cases. With reference to _Mussaenda_, C. Morren held the view that the petal-like sepal was really a bract adherent to the calyx, and incorporating with itself one of the calycine lobes--"soudée au calice et ayant dévorée, en englobant dans sa propre masse, un lobe calicinal." The Belgian _savant_ considers this somewhat improbable explanation as supported by a case wherein there were five calyx lobes of uniform size, and a detached feather-veined leaf proceeding from the side of the ovary lower down ('Bull. Acad. Belg.,' xvii, p. 17, _Fuchsia_, p. 169). [258] In this order _Agrostemma Githago_ offers an illustration of a normally leafy calyx. [259] 'Bull. Bot.,' i, p. 6. [260] Wolff's original opinion was that the stamens were equivalent to so many buds placed in the axil of the petals or sepals (see 'Theoria Generationis,' 1759, § 114)--an opinion which more recently has received the support of Agardh and Endlicher. Wolff himself, however, seems to have abandoned his original notion, for in his memoir, "De formatione intestinorum præcipue tum et de amnio spurio aliisque partibus embryonis gallinacei, nondum visis," &c., in 'Comm. Acad. Petrop.,' xii, p. 403, anno 1766, he considers the stamens as essentially leaves. See also Linn. 'Prolepsis,' § viii; Goethe, 'Metam.,' § 46. [261] Müller (Argov.), in 'Mém. Soc. Phys. et d'Hist. Nat. Genev.,' t. xvii. [262] "If we keep in view the observations which have now been made, we shall not fail to recognise the leaf in all seed-vessels, notwithstanding their manifold forms, their variable structure, and different combinations."--(Goethe, 'Metam.,' § 78.) Wolff, 'N. Comm. Acad. Petrop.,' 1766, xii, p. 403, expresses precisely the same opinion as to the nature of the seed-vessel. [263] 'El. Terat. Veg.,' p. 205. [264] 'Ann. Sc. Nat.,' 4th series, vol. ix, p. 209. [265] 'Adansonia,' iv, p. 70. A similar deviation has been observed by M. van Tieghem in the ovary of _Tropæolum majus_, 'Bull. Soc. Bot. Fr.,' 1865, p. 411. [266] Planchon et Marès, 'Ann. Sc. Nat.,' ser. 5, vol. vi, 1866, p. 228, tab. xii. [267] 'Act. Acad. Nat. Cur.,' 22, 11. 1850, p. 543, t. v, vi. [268] 'Neue Denkschrift der allg. Schweiz. Gesellsch.,' band v. p. 9, tab. 3, 4. [269] 'Ann. Sc. Nat.,' 2 ser., vol. i, p. 308, pl. ix, c. [270] 'Adansonia,' vol. iv, pp. 159, 171. [271] 'Bildungsabweichungen,' &c., tab. iv, figs. 1, 2, 21, 28, 29, &c. [272] 'Bull. Soc. Bot. France,' viii, p. 395. [273] 'Notulæ,' p. 125, atlas, pl. xxxv; and 'Journals of Travels,' 1847, p. 475, _Lonicera_. [274] 'Ann. Science Nat.,' 3rd ser., vol. ix, p. 86, tabs. 5, 6. [275] 'Comptes Rendus,' vol. xviii, March 25th, 1864, and 'Ann. Sc. Nat.,' 3 ser., vol. ii, p. 32. [276] 'Mém. Acad. Sc. Toulous.,' ser. 5, vol. iii. [277] 'Bildungsabweich. Pflanz. Famil.,' p. 89, tab. xi. [278] 'Bull. Soc. Bot. Fr.,' 1865, p. 411. [279] Translated in 'Ann. Sc. Nat.,' 4th series, t. xiv, p. 24. [280] The calyx is not unfrequently excepted. [281] 'Bull. Bot.,' t. i, p. 6. [282] Lindley, 'Theor. Horticult.,' ed. 2, p. 84, f. 17. [283] Gris, 'Bull. Soc. Bot. Fr.,' 1858, vol. v, p. 261, and 'Ann. Sc. Nat.,' ser. 4, vol. ix, p. 80. Planchon, 'Flore des Serres,' vol. i, 1856, p. 129. [284] 'Flora,' 1856, p. 711. [285] 'Theory of Horticult.,' ed. 2, p. 90, f. 25. [286] As considerable interest attaches to the "Plymouth strawberry," and very little is known of it in this country, or on the continent, the author gladly avails himself of this opportunity of inserting an account of it, for which he is indebted to the kindness of Dr. Robert Hogg.--The Plymouth Strawberry (_Fragaria vesca fructu hispido_) is a sort of botanical Dodo upon which many have written, and which few have seen. Many years have elapsed since it was first discovered; and although a century and a half have passed since there was any evidence of its existence, it serves still as an illustration for students in morphology of one of those strange abnormal structures with which the vegetable kingdom abounds. It is to old John Tradescant we are indebted for the earliest record of this plant. Johnson, in his edition of 'Gerard,' says; "Mr. John Tradescant hath told me that he was the first that tooke notice of this strawberry, and that in a woman's garden at Plimouth, whose daughter had gathered and set the roots in her garden, in stead of the common strawberry; but she, finding the fruit not to answer her expectation, intended to throw it away; which labour he spared her in taking it and bestowing it among the louers of such varieties, in whose garden it is yet preserved." Doubtless one of those "lovers" was his friend John Parkinson, who, in the year 1629, thus wrote concerning it: "One strawberry more I promised to shew you, which, although it be a wilde kinde, and of no vse for meate, yet I would not let this discourse passe without giuing you the knowledge of it. It is in leafe much like vnto the ordinary, but differeth in that the flower, if it haue any, is greene, or rather it beareth a small head of greene leaues, many set thicke together like vnto a double ruffe, in the midst whereof standeth the fruit, which, when it is ripe, sheweth to be soft and somewhat reddish, like vnto a strawberry, but with many small harmlesse prickles on them which may be eaten and chewed in the mouth without any maner of offence and is somewhat pleasant as a strawberry; it is no great bearer, but those it doth beare, are set at the toppes of the stalks close together, pleasant to behold, and fit for a gentlewoman to weare on her arme, &c., as a rairitie in stead of a flower." Merret, in his 'Pinax.' published in 1667, says he found it growing in the woods of Hyde Park and Hampstead, and Zanoni was the first to figure it (with the exception of Parkinson's rude woodcut) in his 'Istoria Botanica,' published in 1675. It is mentioned by Morison and also by Ray, the latter of whom inserts it in his Synopsis, but without any habitat; though in his 'Historia Plantarum' he says: "Cantabrigiæ in horto per aliquot annos colui." From this time henceforth the Plymouth strawberry has become a botanical Dodo, nothing more having been seen or heard of it except the mere record of the name. In 1766, M. Duchesne informed the world of the generosity of "M. Monti, Docteur de Philosophie et de Médecine à Boulogne en Italie," who divided with him a dried specimen taken from his own herbarium, "Ce présent prétieux m'ôte toute incertitude sur la nature de ce Fraisier et sur ses caractères monstrueux. Il paroît ne pas avoir aujourd'hui plus d'existence." [287] 'Bull. Soc. Bot. France,' 1856, vol. iii, p. 477. [288] 'Ann. Sc. Nat.,' 3 ser., vol. ix, p. 86, tabs. v, vi. [289] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 695. [290] Ibid., vol. iii, 1856, p. 475. [291] 'Flora,' 1856, p. 712. [292] 'Trans. Linn. Soc.,' vol. xxvi, p. 37. [293] 'Bull. Soc. Bot. France,' 1862, vol. ix, p. 36, tab. i, and also p. 291. [294] Ibid., 1857, vol. iv, p. 761. CHAPTER II. METAMORPHY OF THE FLORAL ORGANS. One of the main arguments adduced by Goethe and others in support of the now generally received doctrine of the essential morphological identity of the various whorls of the flower is derived from the frequent appearance of one organ in the guise of another. The several parts of the flower become, as it is said, metamorphosed; sometimes the change is complete, while at other times there may be every conceivable intermediate condition between one form and another. The sense in which the terms metamorphosis, substitution, transformation, and the like, are herein used has already been explained. For the convenience of arrangement, metamorphosis of the parts of the flower may be divided into several subdivisions, according to the particular organ affected, and according to the special kind or degree of change manifested, the main subdivisions being here classed as Sepalody, Petalody, Staminody, and Pistillody. =Sepalody of the petals.=--This change, spoken of by most authors as retrograde metamorphosis of the petals into sepals, or as a substitution of sepals for petals, is obviously a condition that is in most cases hardly distinguishable from virescence of the corolla, or from multiplication of the sepals. Nor is this of much consequence unless there are some special structural features which render the discrimination a matter of importance, in which case the difficulty is generally easily surmounted. The flower of the Saint-Valèry Apple may perhaps be cited under this head. In the flower in question there are neither stamens nor petals, unless the second or inner of sepals be considered as sepaloid petals (fig. 152). [Illustration: FIG. 152.--Flower of St. Valèry apple, with sepaloid petals.] M. Alph. de Candolle[295] describes an instance in _Primula Auricula_ in which the corolla had assumed the appearance of the calyx, but neither calyx nor corolla in this case possessed perfect stomata. This malformation is much less common than the converse one of calycanthemy. Many of the recorded instances of so-called metamorphosis of the parts of the flower to sepals have occurred in monocotyledonous plants, or others in which the calyx and corolla are of the same colour, and constitute what is frequently termed the perianth; and as this is usually brightly coloured (not green) it is more convenient to group the metamorphoses in question under the general term Petalody, which thus includes all those cases in which the organs of the flower appear in the form of coloured petal-like organs, whether they be true petals or segments of a coloured perianth. As the morphological difference between the organs is one of position merely, there is little objection to be raised to this course, the less so as the term petalody merely conveys an idea of resemblance and not of absolute identity. Petaloid coloration of the ordinary leaves, or of the bracts, is mentioned under the chapter relating to colour. =Petalody of the calyx--Calycanthemy.=--As with the bracts, so the calyx in certain instances is naturally coloured, as in _Delphinium_, _Tropæolum_, and others. In _Mussænda_, _Calycophyllum_, _Usteria_, &c., one or more of the calyx lobes become enlarged normally. Considered teratologically, petaloid coloration of the sepals is either general or partial; in the latter case the nerves retain their green colour longest. There is in cultivation a variety of the primrose called _Primula calycanthema_, in which the upper part of the calyx becomes coloured, so that the flower seems to have two corollas placed one within the other; a similar thing happens in _Mimulus_, in which plant, as the calyx is permanent while the corolla is deciduous, the coloured calyx is a great advantage in a horticultural point of view. Morren[296] says that in order to produce the fine colour of the calyx of _Primula officinalis_ (var. _smaragdina_) the Belgian gardeners cut away the corolla in a very early stage, and that in consequence the colouring matter proper to the corolla is developed in the tube of the calyx, the edges of the limb remaining green, the middle of the limb being purple (_Primula tricolor_). [Illustration: FIG. 153.--Flower of _Mimulus_, with petaloid calyx.] Under this head may be mentioned the occurrence of tubular sepals in place of the ordinary flat ones in _Helleborus olympicus_; only two of th