[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 Mares, '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 versa. 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-morphosis].



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.



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.



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 Linnaeus, 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 (Alsodeiae) 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 Tropaeolum 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 Papilionaceae 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 Gesneraceae, Bignoniaceae, Scrophulariaceae, 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.



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 Compositae 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.



In Orchidaceae 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 Phalaenopsis 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 Tropaeolum, 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! Tropaeolum majus! *Wistaria sinensis. Lupinus. *Cytisus Laburnum! Trifolium repens! *Compositae, 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. Phalaenopsis amabilis! Phalaenopsis Schilleriana. Habenaria. *Orchis morio. mascula. *Dendrobium, sp. Atriplex, sp. Cattleya Mossiae! 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, 'Mem. 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, 'Mem. Acad. Toulouse,' vi, 1862, Salvia. Caspary, 'Verhandl. Phys. OEkon. Gesell. Koenigsberg,' 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 regularite 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] 'Linnaea,' 1837, p. 128.

[225] M. Bureau, 'Bull. Soc. Bot. Fr.,' ix, p. 91, describes two genera of Bignoniaceae 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-morphosis].



CHAPTER I.

IRREGULAR PELORIA.

The term peloria was originally given by Linne 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: pelor], 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!



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 Papilionaceae, 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 Phalaenopsis 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.



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 (Tropaeolum majus), each presenting a supernumerary spur. On these he remarked that "in Tropaeolum 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.

Linne, 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 versa, 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 Compositae, 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."



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 Scrophulariaceae with those of Solanaceae, concluded that the former natural order was only an habitual alteration from the type of the latter. Peloric flowers of Papilionaceae in this way are indistinguishable from those of Rosaceae. 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 peloriae, solo sterili plantatae, 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. aeruginea. 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 Moasiae! Phalaenopsis 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, 'Linnaea,' 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, 'Mem. 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, 'Linnaea,' t. vii, p. 206. Guillemin, 'Archiv. Bot.,' t. ii, p. 1 et 136. Schlechtendal, 'Linnaea,' xii, p. 686. Ernst Meyer, 'Linnaea,' 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.—Orchidaceae, His, 'Jourl. Phys.,' 65, p. 241. Wydler, 'Arch. Bot.,' t. ii, p. 310, tab. xvi. R. Brown, 'Obs. organ. Orchid.,' p. 698. A. Richard, 'Mem. 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, 'Mem. Acad. Sc. Toulous.,' 5 ser., vol. iii. Caspary, 'Schrift. K. Gesellsch. Koenigsberg,' 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 "a force d'irregularite.")—Chelone, Chamisso, 'Linnaea,' 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 Linne's notion that these forms were due to hybridization. It is extracted from Gmelin's edition of the 'Systema Naturae,' 1791, p. 931. "Linariae 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. Naturae prodigium. Ita quidem a Linne. Verisimilor autem videtur ea opinio, quae peloriam pro peculiari degeneratione monstrosa floris habet, in quam inclinare hoc genus (Linaria) prae 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, "Mem. sur les Fumariees a fl. irreg.," 'Ann. Sc. Nat.,' ser. 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] 'Theor. Elem.,' 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, Linne, 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.



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]



In Umbelliferae 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 Euphorbiaceae, 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 europaea), 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 Podocarpeae and Cupressineae (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 Ranunculaceae and Rosaceae, for example, Rosa, Geum, are particularly liable to this change.



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.



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 (Valerianaceae).

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 Cucurbitaceae adherent to the carpels. It is also shown in the cut, fig. 132, borrowed from the 'Gardeners' Chronicle,' 1859, p. 654.



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. Caryophyllaceae,[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. Hypochaeris 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 europaeum. Laurus Sassafras. Tulipa Gesneriana. Convallaria maialis. Colchicum autumnale! (virescent?)

Consult also Turpin, 'Atlas de Goethe,' t. iv, f. 12, Lycium. Engelmann, 'De Anthol.,' Sec. 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.



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 Tropaeolum 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 Actaea 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 Tropaeolum 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 laminae. (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. Actaea 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. *Tropaeolum majus! Geranium, sp.! Triumfetta, sp.! Epilobium hirsutum! OEnothera striata. Rubus, sp. *Rosa, var. cult.! *Trifolium repens! Spiraea 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.,' Sec. 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. Caes. Nat. Cur.,' vol. xiii, 2, p. 1, tab. xli, Tropaeolum. Bischoff, 'Lehrbuch,' 11, 2, p. 27, note, Tropaeolum. Fresenius, 'Mus. Senkenb.,' ii, 35, tab. 4, fig. 5, Actaea. 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.



In the case of frondescent flowers of Tropaeolum 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, Muell. (Adenorophium luxurians, Pohl.), a singular condition has been observed by M. Mueller (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.



Phyllody of the stamens has been most often observed in the following plants:

Anemone nemorosa. coronaria. Delphinium crassicaule. Nymphaea dentata. Tropaeolum 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 laminae, 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 Cruciferae and Umbelliferae. 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.



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.



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 Cucurbitaceae 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.



There are cases, however, in which a part only of the pistillary structure thus becomes foliaceous. Linnaeus, 'Prolepsis,' Sec. 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 placentae; 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 Umbelliferae, 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:

Paeonia officinalis. Ranunculus repens! *Aquilegia vulgaris! Delphinium elatum. crassicaule. Ajacis. amaenum. Nymphaea 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 Primulaceae, 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.



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).



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.



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.



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.



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.



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 Tropaeolum 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 Primulaceae, 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.! Tropaeolum 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. praenitens. Gilia glomeruliflora. Rumex arifolius. scutatus. Salix capraea.

The following list of publications relating to ovular malformations is copied from A. Braun, 'Ueber Polyembryonie und Keimung von Caelobogyne' (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. Gewaechse,' 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, 'Linnaea,' 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 Koenigsberg,' 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, Tropaeolum.

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 Leguminosae; the scales of some begonias; the tendrils of Bignonia, Cobaea, &c.

The presence of two small green laminae 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.



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.



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 Cruciferae, of which family the last-named plant is a member, are particularly liable to this malformation, as also are the Rosaceae, 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 a 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 "Organogenie," 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 Leguminosae 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 Nymphaea 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 paleae 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 Bambusaceae,[292] refers to an illustration in which "the lowest glumes generally, and the lowest paleae occasionally, had the appearance of miniature leaves, with vaginae, ligules and cilia, enveloping, however, perfect fertile spiculae; 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."