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.
This volume is issued to the Subscribers to the RAY SOCIETY for the Year 1868.
An Account of the Principal Deviations from the Usual Construction of Plants
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.
DEVIATIONS FROM ORDINARY ARRANGEMENT 1
PART I.—UNION OF ORGANS 8
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.
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
Fission of axile organs, 60—Of foliar organs, 61—Of petals, 66—Of stamens, 68—Of carpels, 68.
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.
Solution of calyx from ovary, 77—Of stamens from petals, 82.
PART III.—ALTERATIONS OF POSITION 83
Displacement of bulbs, 84—Of inflorescence, 85—Of leaves, 87—Of parts of flowers, 91—Of carpels, 96—Of placentas and ovules, 96.
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.
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 gemmae 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 Compositae, 188—Heterotaxy affecting the inflorescence, 188—Supra-soriferous ferns, 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.
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.
DEVIATIONS FROM ORDINARY FORM 213
PART I.—STASIMORPHY 216
PERSISTENCE OF JUVENILE FORMS 217
Stasimorphy in leaves of Conifers, 217—Regular peloria, 219.
PART II.—PLEIOMORPHY 228
IRREGULAR PELORIA 228
PART III.—METAMORPHY 240
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.
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
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.
Heterophylly, 330—Dimorphism, 333—Sports or bud-variations, 336.
ALTERATIONS OF COLOUR 337
Albinism, 337—Virescence, 338—Chromatism, 339.
DEVIATIONS FROM ORDINARY NUMBER 340
PART I.—INCREASED NUMBER OF ORGANS 343
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.
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
SUPPRESSION OF AXILE ORGANS 393
Acaulosia, 393—Non-development of peduncle, 393—Nature of calyx-tube (Casimir de Candolle), 394—Suppression of columella, 395.
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.
DEVIATIONS FROM ORDINARY SIZE AND CONSISTENCE 413
PART I—HYPERTROPHY 416
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.
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.
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
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.
Formation of scales, 470—Of hairs, 472—Of glands, 473—Of tendrils, 473.
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.
Double flowers, varieties of, 491—Causes of production, 491—Relation to variegated foliage, 497—List of plants producing, 499.
INDEX TO SUBJECTS 511
INDEX OF NAMES OF PLANTS 517
LIST OF ILLUSTRATIONS.
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 Nymphaea 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 Nymphaea 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 Baeckea 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 (Mueller) 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. Placentae 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 Crataegus 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 Alexandrae 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
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. Linnaeus 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, Jaeger, 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 'Elements,' to be considered as referring to limited portions only and not to the whole subject.
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.'
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. Following Goethe, these changes in the course of development are sometimes called metamorphoses. In this way Agardh 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 vertebrae, &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. It is hoped that both the lists of books and of plants are sufficiently full for all general purposes.
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 versa, 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.
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?
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 Gaertner, 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. 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.
 An excellent summary of the history of Vegetable Teratology is given in Kirschleger's 'Essai historique de la Teratologie Vegetale,' Strasburg, 1845.
 In some instances diagrams and formulae 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.
 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.
 Agardh, "Theoria Syst. Plant.," p. xxiii.
 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.
 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.
 On this subject see a paper of M. Naudin in the 'Comptes Rendus,' 1867, t. 64, pp. 929-933.
 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.
 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.
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.
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.
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.
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.
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 AEtna, are really cases where fusion has taken place between several of the branches, or suckers, thrown out from the same original stem. 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.
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.
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.
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. The pedicels of Streptocarpus Rexii have also been observed in a fasciated state.
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, 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. Linnaeus, 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 fasciae evadat et compressus" (Linn., 'Phil. Bot.,' 274). A similar opinion was held by J. D. Major in a singular book entitled 'De Planta, Monstrosa, Gottorpiensi,' Schleswig, 1665, wherein the stem of a Chrysanthemum is depicted in the fasciated condition.
The striae, 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 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 deg.], 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 deg.], 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 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 saepe in Ranunculo, Beta, Asparago, Hesperide Pinu, Celosia, Tragopogone, Scorzonera Cotula foetida," Linnaeus 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.
[Greek: alpha]. Herbaceous.
Ranunculus tripartitus. * bulbosus! Philonotis. Delphinium elatum. * sp.! Hesperis matronalis. *Cheiranthus Cheiri! *Matthiola incana! *Brassica oleracea! var. pl. inflor. Linum usitatissimum! Althaea rosea! Lavatera trimestris. Geranii sp. Tropaeolum 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. Stapeliae sp. Lysimachia vulgaris! Androsace maxima. Primula veris inflor.! denticulata inflor.! Polemonium coeruleum. Convolvulus sepium! arvensis! Plantago media. *Euphorbia Characias. exigua. * Cyparissias. Suaeda maritima. *Celosia sp. Beta vulgaris inflor.! Phytolacca sp.
[Greek: beta]. Woody.
Berberis vulgaris. Hibiscus syriacus! Acer pseudo-platanus! Dodonaea 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.! Spiraea 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. Suaeda fruticosa. Ulmus campestris. Alnus incana. Salix vitellina, &c.! Thuja orientalis. Pinus pinaster! sylvestris! Abies excelsa! Taxus baccata. Larix europoea.
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. Tiliae,' Berlin, 1861.) It is also stated that this condition is not perpetuated by grafting.
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 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 notices something of the same kind in the leaf of Amorpha fruticosa; Treviranus in that of Aristolochia Sipho.
M. Puel 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.
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. 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, 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 Tropaeolum 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. M. Clos 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.
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. 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.
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.
Cohesion of the petals.—Linnaeus mentions the occurrence of cohesion of the petals in Saponaria. 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. 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. 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, 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.
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 europaea! 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? Codiaeum 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).
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.
 See a curious instance of this kind in the branches of Pinus. 'Regel. Garten Flora,' vol. 8, tab. 268.
 'Bull. Soc. Bot. France,' 1860, p. 881.
 Ibid., 1861, p. 708.
 Ibid., 1860, p. 923.
 'Proc. Linn. Soc.,' April 5, 1853.
 'Organ. Veget.,' pl. iii, fig. 1.
 'Bull. Acad. Roy. Bruxelles,' t. xviii, p. i and p. 591.
 'Linnaea,' tom. 13, p. 383.
 'Verhandl. Nat. Hist. Vereins,' 1859, Bonn, tom. xvi, tab. 3.
 'Bull. Soc. Bot. Fr.,' vol. i, p. 62.
 'Report of Internat. Bot. Congress,' London, 1866, p. 131, tab. vii, figs. 10-13.
 'Bull. Acad. Roy. Belg.,' t. xviii, 2nd part, p. 179.
 D. C., 'Organ. Veget.,' pl. xvii, fig. 3, and pl. xlviii, fig. 2.
 'Mem. Acad. Toulouse,' 1862.
 Bonnet, 'Recherches Us. feuill.,' pl. xxi, fig. 2.
 De Candolle, 'Mem. Leg.,' pl. v, fig. 14.
 'Phil. Bot.,' Sec. 125.
 'Nov. Act. Acad. Nat. Cur.,' 14, p. 642, t. xxxvii.
 'Journal of the Linn. Soc. Bot.,' vol. iv, p. 55.
 'Bull. Acad. Roy. Bruxelles,' 1838, t. v, p. 582. 'Bull. Acad. Roy. Belg.,' 1852, t. xix, part iii, p. 437.
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.