Adhesion between the axes of the same plant is sufficiently treated of under the head of Cohesion, from which it is in this instance impossible to make a distinction. Adhesion of the inflorescence is necessarily a frequent accompaniment of fasciation and cohesion of the branches.

Adhesion of foliar organs may occur either between the margins or between the surfaces of the affected parts; in the former case there is almost necessarily more or less displacement and change of direction, such as a twisting of the stem and a vertical rather than a horizontal attachment of the foliar organ to it; hence it generally forms but a part of other and more important deviations.

Adhesion of leaves by their surfaces.—The union of leaves by their surfaces is not of very frequent occurrence, many of the instances cited being truly referable to other conditions. Bonnet describes the union of two lettuce leaves, and Turpin that of two leaves of Agave americana, in which latter the upper surface of one leaf was adherent to the lower surface of the leaf next above it, and I have myself met with similar instances in the wallflower and in lettuce and cabbage leaves; other instances have been mentioned in Saxifraga, Gesnera, &c.[30]

In these cases, owing to the non-development of the internodes, the nascent leaves are closely packed, and the conditions for adhesion are favorable, but in most of the so-called cases of adhesion of leaf to leaf by the surface, a preferable explanation is afforded either by an exuberant development (hypertrophy) or by chorisis (see sections on those subjects). Thus, when a leaf of this kind is apparently so united, that the lower surface of one is adherent to the corresponding surface of another, the phenomenon is probably due rather to extra development or to fission. There is an exception to this, however, in the case of two vertically-erect leaves on opposite sides of the stem; here the two upper or inner surfaces may become adherent, as in an orange, where two leaves were thus united, the terminal bud between them being suppressed or abortive.

Adhesion between the membranous bract of Narcissus poeticus and the upper surface of the leaf is described by Moquin.[31] The same author mentions having seen a remarkable example of adhesion in the involucels of Caucalis leptophylla, the bracts of which were soldered to the outer surface of the flowers. M. Bureau[32] mentions an instance wherein the spathe of Narcissus biflorus was partially twisted in such a manner that the lower surface of its median nerve was adherent to the corresponding surface of one of the sepals, mid-rib to mid-rib, thus apparently confirming a law of G. de Hilaire, that when two parts of the same individual unite, they generally do so by the corresponding surfaces or edges, but the rule is probably not so general in its application as has been supposed.

Adhesion of foliar to axile organs.—The appendicular organs may likewise be found united to the axile ones. This union takes place in many ways; sometimes the leaves do not become detached from the stem for a considerable distance, as in the so-called decurrent leaves, at other times the leaves are prolonged at their base into lobes, which are directed along the stem, and are united with it. Turpin records a tendril of a vine which was fused with the stem for some distance, and bore leaves and other tendrils. Union of the leaf or bract with the flower-stalk is not uncommon. It occurs normally in the Lime and other plants.

Adhesion of the sepals to the petals is spoken of by Morren as calyphyomy, [Greek: kalyx phyomai.][33] Moquin cites an instance in Geranium nodosum, in which one petal was united by its lower surface to one of the segments of the calyx. A similar circumstance has been observed in Petunia violacea by Morren. Duchartre describes an instance wherein one of the outer sepals of Cattleya Forbesii was adherent to the labellum.[34]

Adhesion of the stamens to the petals is of common occurrence under natural circumstances. Cassini has described a malformation of Centaurea collina, in which two of the five stamens were completely grafted with the corolla, the three others remaining perfectly free. Adhesion of the petals to the column is not of infrequent occurrence among Orchids. I have observed cases of the adhesion of the segments of the perianth to the stamen in Ophrys aranifera, Odontoglossum, sp. &c. It is the ordinary condition in Gongora and some other genera. I have seen it also in Lilium lancifolium. Some forms of Crocus, occasionally met with, present a very singular appearance, owing to the adhesion of the stamens to the outer segments of the perianth, the former, moreover, being partially petaloid in aspect. M. de la Vaud[35] speaks of a similar union in Tigridia pavonia. Morren[36] describes a malformation of Fuchsia wherein the petals were so completely adherent to the stamens, that the former were dragged out of their ordinary position, so as to become opposite to the sepals; the fusion was here so complete that, no trace of it could be seen externally. It should be remarked that it was the outer series of stamens that were thus fused.[37]



Adhesion of stamens to pistils.—The stamens also may be united to the pistils, as in gynandrous plants. Moquin speaks of such a case in a Scabious; M. Clos in Verbascum australe.[38] I have seen cases of the same kind in the Wallflower, Cowslip (Primula veris), Tulip, Orange, in the garden Azalea and other plants.

Miscellaneous adhesions.—Sometimes organs, comparatively speaking, widely separated one from the other, become united together. Miquel has recorded the union of a stigma with the middle lobe of the lower lip of the corolla of Salvia pratensis.[39] In the accompanying figure [fig. 13], taken from a double wallflower, there is shown an adhesion between a petal and an open carpel on the one side, and a stamen on the other.

Moquin speaks of some pears, which were united, at an early stage, with one or two small leaves borne by the peduncle and grafted to the fruit by the whole of their upper surface. As the pear increased in size the leaves became detached from it, leaving on the surface of the fruit an impression of the same form as the leaf, and differing in colour from the rest of the surface of the fruit. Traces of the principal nerves were seen on the pear.



It is curious to notice how very rare it is for the calyx to adhere to the ovary in flowers where that organ is normally superior. The "calyx inferus" seems scarcely ever to become "calyx superus," while, on the other hand, the "calyx normaliter superus" frequently becomes inferior from detachment from, or from want of union with the surface of the ovary.

Adhesion of fruit to branch.—Of this Mr. Berkeley[40] cites an instance in a vegetable marrow (Cucumis), where a female flower had become confluent with the branch, at whose base it was placed, and also with two or more flowers at the upper part of the same branch, so as to make an oblique scar running down from the apex of the fruit to the branch.

Synanthy.—Adhesion of two or more flowers takes place in various ways; sometimes merely the stalks are united together, so that we have a single peduncle, bearing at its extremity two flowers placed in approximation very slightly adherent one to the other. In this manner I have seen three flowers of the vegetable marrow on a common stalk, the flowers themselves being only united at the extreme base. Occasionally cases may be met with wherein the pedicels of a stalked flower become adherent to the side of a sessile flower. I have noticed this commonly in Umbelliferae. Union of this kind occurs frequently in the common cornel (Cornus), wherein one of the lower flowers becomes adherent to one of the upper ones. In De Candolle's 'Organographie Vegetale,' Plates 14 and 15, are figured cases of fusion of the flower stems of the Hyacinth and of a Centaurea. In other cases the union involves not only the stalk but the flowers themselves; thus fusion of the flowers is a common accompaniment of fasciation, as was the case in the Campanula figured in the cut (fig. 14).



Synanthy may take place without much derangement of the structure of either flower, or the union may be attended with abortion or suppression of some of the parts of one or both flowers. Occasionally this union is carried to such an extent that a bloom appears to be single, when it is, in reality, composed of two or more, the parts of which have become not only fused, but, as it were, thrust into and completely incorporated one with another, and in such a manner as to occupy the place of some parts of the flower which have been suppressed. It must not be overlooked that this adhesion of one flower to another is a very common occurrence under natural circumstances, as in Lonicera, in the common tomato, in Pomax, Opercularia, Symphyomyrtus, &c., while the large size of some of the cultivated sunflowers is in like manner due to the union of two or more flower-heads.

One of the simplest instances of synanthy is that mentioned by M. Duchartre,[41] in which two flowers of a hyacinth were united together simply by means of two segments of the perianth one from each flower. A similar occurrence has been cited by M. Gay in Narcissus chrysanthus. In like manner the blossoms of Fuchsias or Loniceras occasionally become adherent merely by their surface, without involving any other change in the conformation of the flowers. M. Maugin alludes to a case of this kind in Aristolochia Clematitis.[42]

But it is more usual for some of the organs to be suppressed, so that the number of existing parts is less than would be the case in two or more uncombined flowers. A few illustrations will exemplify this. In two flowers of Matthiola incana, that I observed to be joined together, there were eight sepals, eight petals, and ten perfect stamens, eight long and two short, instead of twelve. Closer examination showed that the point of union between the two flowers occurred just where, under ordinary circumstances, the two short stamens would be. In this instance but little suppression had occurred. In similar flowers of Narcissus incomparabilis I remarked a ten-parted perianth, ten stamens within a single cup, two styles, and a five-celled ovary. Here, then, it would appear that two segments of the perianth, two stamens, and one carpel were suppressed. In a Polyanthus there were nine sepals, nine petals, nine stamens, and a double ovary.



As an illustration of a more complicated nature reference may be made to three flowers of Aconitum Napellus, figured by A. de Chamisso, 'Linnaea,' vol. vii, 1832, p. 205, tab. vii, figs. 1, 2. In this specimen the two outer blossoms had each four sepals present, namely, the upper hooded one, one of the lateral sepals, and both of the inferior ones; the central flower had only the upper sepal and one other, probably one of the lower sepals; thus there were but ten sepals instead of fifteen. The nectary-like petals, the stamens, and pistils were all present in the lateral flowers, but were completely suppressed in the middle one. A less degree of suppression was exemplified in a triple flower of Calanthe vestita sent me by Dr. Moore, of Glasnevin, in which all the parts usually existing in three separate flowers were to be found, with the exception of the spur belonging to the labellum of the middle flower (figs. 15, 16).

One of the most common malformations in the Foxglove (Digitalis) results from the fusion of several of the terminal flowers into one. In these cases the number of parts is very variable in different instances; the sepals are more or less blended together, and the corollas as well as the stamens are usually free and distinct, the latter often of equal length, so that the blossom, although truly complex, is, as to its external form, less irregular than under natural circumstances. The centre of these flowers is occupied by a two to five-celled pistil, between the carpels of which, not unfrequently, the stem of the plant projects, bearing on its sides bracts and rudimentary flowers. (See Prolification.) An instance of this nature is figured in the 'Gardeners' Chronicle,' 1850, p. 435, from which the cut (fig. 17) is borrowed.



One of the most singular recorded instances of changes connected with fusion of the flowers is that cited by Reinsch,[43] where two female flowers of Salix cinerea were so united with a male one as to produce an hermaphrodite blossom.

It follows, from what has been said, that the number of parts that are met with in these fused flowers varies according to the number of blossoms and of the organs which have been suppressed. Comparatively rarely do we find all the organs present; but when two flowers are united together we find every possible variety between the number of parts naturally belonging to the two flowers and that belonging to a single one. Sometimes instances are met with wherein the calyx does not present the normal number of parts, while the other parts of the flower are in excess. I have seen in a Calceolaria a single calyx, with the ordinary number of sepals, enclosing two corollas, adherent simply by their upper lips, and containing stamens and pistils in the usual way. In this instance, then, the sepals of one flower must have been suppressed, while no such suppression took place in the other parts of the flower.

Professor Charles Morren paid special attention to the various methods in which the flowers of Calceolarias may become fused, and to the complications that ensue from the suppression of some parts, the complete amalgamation of others, &c. Referring the reader to the Belgian savant's papers for the full details of the changes observed, it is only necessary to allude to a few of the most salient features.



Sometimes the upper lips of two flowers are fused into one, the two lower remaining distinct. In other cases, the upper lip disappears altogether, while there are two lower lips placed opposite one another;, of the stamens, sometimes the outermost, at other times the innermost disappear.[44]

Occasionally there appears to be, as it were, a transference of the parts of one flower to another. One of the simplest and most intelligible cases of this kind is recorded by Wigand in the 'Flora' for 1856, in a compound flower of Polygonatum anceps, in which within a twelve-parted perianth there were twelve stamens and two pistils, one four-celled, the other two-celled; hence it would appear as if a carpel belonging to one flower had become united to those constituting the pistil of the adjacent one. Among Orchids this fusion of some of the elements of different flowers, together with the suppression of others, is carried to such an extent as to render the real structure difficult to decipher. Sometimes flowers of Ophrys aranifera, at first sight seeming normal as to the number, and almost so as regards the arrangement of their parts, have yet, on examination, proved to be the result of a confluence of two flowers. Mr. Moggridge has observed similar phenomena in the same species at Mentone.

Sometimes the fusion affects flowers belonging to different branches of the same inflorescence, as in Centranthus ruber, described by Buchenau, 'Flora,' 1857, p. 293, and even a blossom of one generation of axes may be united with a flower belonging to another generation. Thus M. Michalet[45] speaks of a case wherein the terminal flower of Betonica alopecuros was affected with Peloria, and fused with an adjacent one belonging to a secondary axis of inflorescence, and not yet expanded. This latter flower had no calyx, but in its place were three bracts, surrounding the corolla; this again was united to the calyx of the terminal bloom in a most singular manner, the limb of the corolla and that of the calyx being so joined one to the other as to form but a single tube. It is not uncommon, as has been before stated, to find two corollas enclosed within one calyx, but this is probably the only recorded instance of the fusion of the calyx and corolla of two different flowers belonging to two different axes.

From the preceding details, as well as from others which it is not necessary to give in this place, it would appear that synanthy is more liable to occur where the flowers are naturally crowded together[46] than where they are remote; so too, the upper or younger portions of the inflorescence are those most subject to this change. In like manner the derangements consequent on the coalescence of flowers are often more grave in the central organs, which are most exposed to pressure, and have the least opportunities of resisting the effects of that agency, than they are in the outer portions of the flowers where growth is less restricted.

Morren in his papers on synanthic Calceolarias, before referred to, considers that the direction in which fusion acts is centripetal, e.g. from the circumference towards the centre of the flower, thus reversing the natural order of things. He considers that there is a radical antagonism between the normal organizing forces and the teratological disorganizing forces, and explains in this way the frequent sterility of monsters from an imperfect formation of stamens, or pistils, or both.

The greater tendency in synanthic flowers of parts of one whorl to adhere to the corresponding organs in another flower has often been remarked, though the dislocation of parts may be so great as to prevent this from being carried out in all cases. It appears also that synanthy is more frequently met with among flowers which have an inferior ovary than in those in which the relative position of the organ in question is reversed. This remark applies particularly to individual cases; the proportion as regards the genera may not be so large. The explanation of this must of course depend on the circumstances of each particular case; and it would be wrong to attempt to lay down a general rule, when organogenists have not yet fully decided in what plants the inferior ovary is an axial structure, and in what others the appearance is due to the adhesion of the base of the calyx to the carpels.

The list which follows is not intended as a complete one, but it may serve to show what plants are more particularly subject to this anomaly; the * indicates unusual frequency of occurrence, the ! signifies that the writer has himself seen instances in the plants named. Many of the recorded cases of Synanthy are really cases of adhesion of the inflorescence rather than of the flowers.

Ranunculus Lingua. bulbosus! Aconitum Napellus. Delphinium sp.! Matthiola incana! Arabis sagittata. Silene sp. Reseda odorata! Vitis vinifera. Citrus aurantium. *Fuchsia var. hort.! OEnothera sp. Saxifraga sp. Podalyria myrtillifolia. Prunus Armeniaca. spinosa. Pyrus Malus. Persica vulgaris. Crataegus monogyna. Robinia pseudacacia. Gleditschia triacanthos. Syringa persica. Cornus sanguinea. Viburnum sp. *Lonicera sp. plur! Centranthus ruber! Valantia cruciata. Centaurea moschata. Jacea. Zinnia elegans. Zinnia revoluta. Helianthus sp.! Spilanthes oleracea. Dahlia. *Leontodon Taraxacum! Senecio Doria. Cichorium Intybus. Lactuca sativa. Anthemis retusa. *Campanula medium! persicifolia. Azalea indica! Vinca minor. Atropa Belladonna. *Solanum Lycopersicum! *Petunia violacea! Galeopsis ochroleuca. Betonica alopecuros. *Digitalis purpurea! *Antirrhinum majus! *Linaria purpurea! *Pedicularis sylvatica! *Calceolaria var. hort.! Scrophularia nodosa. Salpiglossis straminea. Streptocarpus Rexii. *Gesnera var. hort.! AEschynanthus sp.! Thyrsacanthus rutilans! Anagallis collina. *Primula veris! Auricula. *Primula acaulis, var. umbellata! elatior? * sinensis! Aristolochia Clematitis. Blitum sp. Chenopodium sp. Rumex sp. Salix cinerea. *Hyacinthus orientalis! Lilium bulbiferum! croceum, et sp. alix, pl. Tulipa, sp. Polygonatum anceps. Fritillaria imperalis! Agave americana. Iris versicolor. sambucina. Crocus, sp. Colchicum autumnale. Narcissus incomparabilis! Tazetta. biflorus. chrysanthus. *Ophrys aranifera! Calanthe vestita! Oncidium bicolor. ornithorhyncum. &c. &c.

In addition to the works before cited, additional information on this subject may be gained from the following:—Jaeger, 'Missbilld.,' p. 92. v. Schlechtend, 'Bot. Zeit.,' 1856, Robinia. Weber, 'Verhandl. Nat. Hist. Vereins. Preuss. Rheinl.,' 1849, p. 290, Primula. Hincks, 'Rep. Brit. Assoc. Newcastle,' 1838, Salpiglossis. Clos, 'Mem. Acad. Toulouse,' vol. vi, 1862, Anagallis. Wigand, 'Flora,' 1856, tab. 8, Pedicularis. Henfrey, 'Botan. Gazette,' i, p. 280, Reseda. P. Reinsch, 'Flora,' 1860, tab. 7, Petasites. Weber, Verhandl. Nat. Hist. Vereins. f.d. Preuss. Rheinl. u. Westphal.,' 1860, p. 332, tabs. 6 et 7, Prunus, Persica, Campanula, Taraxacum, Saxifraga, Silene, Hyacinthus, &c. Miquel, 'Linnaea,' xi, p. 423, Colchicum. Michel, 'Traite du Citronnier,' tab. 6, Citrus.

Syncarpy.—In the preceding section it has been shown that the carpels, like other parts of the flower, are subject to be united together. This union may either take place between the carpels of a single flower or between the pistils of different flowers. In the latter case the other floral whorls are generally more or less altered. Where, however, the ovary is, as it is called, inferior, it may happen that the pistils of different flowers may coalesce more or less without much alteration in the other parts of the flower, as happens normally in many Caprifoliaceae, Rubiaceae, &c. &c. In some of these cases it must be remembered that the real structure of the apparent fruit is not made out beyond dispute, the main points of controversy being as to what, if any, share the dilated fruit-stalk or axis takes in the formation of such organs. Again, it will be borne in mind that in some cases the so-called fruit is made up of a number of flowers all fused together, as in the Mulberry or the Pineapple, in which plants what is, in ordinary language, called the fruit really consists of the whole mass of flowers constituting the inflorescence fused together. Union of the fruits may also in some cases take place between the carpels after the fall of the other floral whorls, particularly when the outer layers of the pericarp assume a succulent condition, so that under the general head of syncarpy really different conditions are almost necessarily grouped together, and, in seeking to investigate the causes of the phenomenon, the particular circumstances of each individual case must be taken into account. Syncarpy takes place in various degrees; sometimes only the stalks are joined; at other times the whole extent of the fruit, as in cherries, &c. This peculiarity did not escape the observant mind of Shakespeare—

"A double cherry seeming parted. But yet a union in partition, Two lovely berries moulded on one stem." 'Midsummer Night's Dream,' act iii, sc. 2.

A similar union has been observed in peaches, gooseberries, gourds, melons, and a great many other fruits. In the Barbarossa grape I have frequently seen a fusion of two, three, four or more berries quite at the end of the bunch, so that the clusters were terminated by a compound grape. Seringe has remarked sometimes two, sometimes three, fruits of Ranunculus tripartitus soldered together. He has also seen three melons similarly joined.[47] Turpin mentions having seen a complete union between the three smooth and leathery pericarps which are naturally separate and enclosed within the spiny cupule of the chestnut.[48] Poiteau and Turpin have figured and described in their treatise on fruit trees, under the name of Nefle de Correa, four or five medlars, joined together and surmounted by all the persistent leaflets of the calyces.[49]

A very remarkable example of Syncarpy has been recorded by E. Koenig in which nine strawberries were borne on one stem (Fragaria botryformis),[50] and a similar malformation has been observed in the Pineapple.

When two fruits are united together they may be of about equal size, while in other cases one of the two is much smaller than the other. This was the case in two cucumbers given to me by Mr. James Salter. These were united together along their whole length excepting at the very tips; the upper one of the two was much larger than the lower, and contained three cells, the lower fruit was one-celled by suppression. Both fruits were curved, the curvature being evidently due to the more rapid growth of the upper as compared with the lower one.



In many of these cases, where the fruits are united by their bases, the summits become separated one from the other, so as to resemble the letter V. Such divergence is of frequent occurrence where fruits are united by their stalks, because, as growth goes on, the tendency must necessarily be towards separation and divergence of the tips of the fruit.

In some cases of Syncarpy the fusion and interpenetration of the carpels is carried to such an extent that it is very difficult to trace on the outer surface the lines of union. The fruit in these cases resembles a single one of much larger size than usual. Moquin mentions a double apple in which the connection was so close that the fruit was not very different in form from what is customary, and a similar thing happens with the tomato. In the case of stone-fruits it sometimes happens, not only that the outer portions are adherent, but that the stones are so likewise.

M. Roeper has observed two apples grafted together, one of which had its stalk broken, and seemed evidently borne and nourished by the other apple;[51] and a similar occurrence happens not infrequently in the cucumber. Moquin has seen three united cherries having only a single stalk jointed to the central fruit, the lateral cherries having each a slight depression or cicatrix marking the situation of the suppressed stalks. Schlotterbec has figured three apples presenting precisely similar appearances.[52]

Fusion of two or more nuts (Corylus) is not uncommon; I have seen as many as five so united.[53] In these cases the fruits may be united together in a ring or in linear series.

In some Leguminosae, contrary to the general rule in the order, more than one carpel is found; thus peas, French beans, and other similar plants, are occasionally met with having two or more pods within the same calyx, and in Gleditschia triacanthos and Caesalpinia digyna this is so commonly the case as to be considered almost the normal state. (De Cand. 'Mem. Leg.,' pl. 2, fig. 6; pl. 3, fig. 2.) At times these carpels become fused together, and it becomes difficult, when the traces of the flower have disappeared, to ascertain whether these carpels were formed in one flower, or whether they were the result of the fusion of several blossoms. I have seen an instance of this kind in a plum in which there were two carpels in the same flower, the one being partially fused to the other. The nature of such cases may usually be determined by an inspection of the peduncle which shows no traces of fusion. (See chapter on Multiplication.)

When, however, the fruits are sessile, and they become grafted together, the kind of syncarpy is difficult to distinguish. It, may, nevertheless, be said as a general rule that the union brought about by the approximation of two fruits, after the fall of the floral whorls, is never so complete or so intimate as that determined by synanthy; and also that in those cases where there are supernumerary carpels in the flower, and those carpels become united together, they are rarely so completely fused that their individuality is lost.

An analogous phenomenon takes place not uncommonly in mosses, the spore capsules of which become united together in various ways and degrees. Schimper[54] cites the following species as subject to this anomaly:—Buxbaumia indusiata, Leskea sericea, Hypnum lutescens, Anomodon alternatus, Clinacium dendroides, Bryum caespititium, Brachythecium plumosum, Mnium serratum, Splachnum vasculosum. It has also been observed in Trichostomum rigidulum and Hypnum triquetrum.

In addition to the authorities already mentioned, the reader may consult Moquin-Tandon, 'El. Ter. Veg.,' p. 270. Turpin. 'Mem. greffe. Ann. Sc. Nat.,' ser. i, t. xxiv, p. 334. De Candolle, 'Organ. Veget.,' t. i. Duhamel, 'Phys. des Arbres,' t. i, p. 304, tab. xiii, xiv. Weber. 'Verhandl. Nat. Hist. Vereina f. d. Preuss. Rheinl. u. Westphal.,' 1860, p. 332, tab. vi. et vii.

Synspermy, or Union of the Seeds.—Seeds may be united together in various degrees, either by their integuments,[55] or by their inner parts. Such union of the seeds, however, is of rare occurrence. It takes place normally, to a slight extent, in certain cultivated forms of cotton, wherein the seeds are aggregated together into a reniform mass, whence the term kidney cotton. Union of the parts of the embryo is treated under another head (see Synophty).

Adhesion between the axes of different plants.—Under this head may be classed the union that takes place between the stems, branches, or roots of different plants of the same species, and that which occurs between individuals of different species; the first is not very different in its nature from cohesion of the branches of the same plant (figs. 21, 22). It finds its parallel, under natural circumstances, among the lower cryptogams, in which it often happens that several individual plants, originally distinct, become inseparably blended together into one mass. In the gardening operations of inarching, and to some extent in budding, this adhesion of axis to axis occurs, the union taking place the more readily in proportion as the contact between the younger growing portions of the two axes respectively is close. The huge size of some trees has been, in some cases, attributed to the adnation of different stems. This is said to be the case with the famous plane trees of Bujukdere, near Constantinople, and in which nine trunks are more or less united together.[56]



A similar anastomosis may take place in the roots. Lindley cites a case wherein two carrots, of the white Belgian and the red Surrey varieties respectively, had grown so close to each other that each twisted half round the other, so that they ultimately became soldered together; the most singular thing with reference to this union was, that the red carrot (fig. 23, b), with its small overgrown part above the junction, took the colour and large dimensions of the white Belgian (d), which, in like manner, with its larger head above the joining (a), took the colour and small dimensions of the red one at and below the union (e d). The respective qualities of the two roots were thus transposed, while the upper portions or crowns were unaffected: the root of one, naturally weak, became distended and enlarged by the abundant matter poured into it by its new crown; and in like manner the root of the other, naturally vigorous, was starved by insufficient food derived from the new crown, and became diminutive and shrunken (see Synophty).



The explanation of the fact that the stumps of felled fir trees occasionally continue to grow, and to deposit fresh zones of wood over the stump, depends on similar facts. In Abies pectinata, says Goeppert,[57] the roots of different individuals frequently unite; hence if one be cut down, its stump may continue to live, being supplied with nourishment from the adjacent trees to which it is adherent by means of its roots.



A not uncommon malformation in mushrooms arises from the confluence of their stalks (fig. 24), and when the union takes place by means of the pilei, it sometimes happens, during growth, that the one fungus is detached from its attachment to the ground, and is borne up with the other, sometimes, even, being found in an inverted position on the top of its fellow.[58]

The garden operations of budding, grafting and inarching have already been alluded to as furnishing illustrations of adhesion, but it may be well to refer briefly to certain other interesting examples of adhesion induced artificially; thus, the employment of the root as a stock, "root-grafting," is now largely practised with some plants, as affording a quicker means of propagation than by cuttings; and a still more curious illustration may be cited in the fact that it has also been found possible to graft a scion on the leaf in the orange.[59]



Mr. Darwin, in his work on the 'Variation of Animals and Plants,' vol. i, p. 395, alludes to the two following remarkable cases of fusion:—"The author of 'Des Jacinthes' (Amsterdam, 1768, p. 124) says that bulbs of blue and red hyacinths may be cut in two, and that they will grow together, and throw up a united stem (and this Mr. Darwin has himself seen), with flowers of the two colours on the opposite sides. But the remarkable point is, that flowers are sometimes produced with the two colours blended together." In the second case related by Mr. Trail, about sixty blue and white potatoes were cut in halves through the eyes or buds, and the halves were then joined, the other buds being destroyed. Union took place, and some of the united tubers produced white, others blue, while some produced tubers partly white and partly blue.

Adhesion of the axes of plants belonging to different species is a more singular occurrence than the former, and is of some interest as connected with the operation of grafting. As a general rule horticulturists are of opinion, and their opinion is borne out by facts, that the operation of grafting, to be successful, must be practised on plants of close botanical affinity. On the other hand, it is equally true that some plants very closely allied cannot be propagated in this manner. Contact between the younger growing tissues is essential to successful grafting as practised by the gardener, and is probably quite as necessary in those cases where the process takes place naturally. Although there is little doubt but that some of the recorded instances of natural or artificial grafting of plants of distant botanical affinities are untrustworthy, yet the instances of adhesion between widely different plants are too numerous and too well attested to allow of doubt. Moreover, when parasitical plants are considered, such as the Orobanches, the Cuscutas, and specially the mistleto (Viscum), which may be found growing on plants of very varied botanical relationship, the occurrence of occasional adhesion between plants of distant affinity is not so much to be wondered at. Union between the haulms of wheat and rye, and other grasses, has been recorded[60]. Moquin-Tandon[61] relates a case wherein, by accident, a branch of a species of Sophora passed through the fork, made by two diverging branches of an elder (Sambucus), growing in the Jardin des Plantes of Toulouse. The branch of the Sophora contracted a firm adhesion to the elder, and what is remarkable is that, although the latter has much softer wood than the former, yet the branch of the harder wooded tree was flattened, as if subjected to great pressure[62]. It is possible that some of the cases similar to those spoken of by Columella, Virgil[63], and other classical writers, may have originated in the accidental admission of seeds into the crevices of trees; in time the seeds grew, and as they did so, the young plants contracted an adhesion to the supporting tree. Some of the instances recorded by classical writers may be attributed to intentional or accidental fallacy, as in the so-called "greffe des charlatans" of more modern days.

Adhesion of the roots of different species has been effected artificially, as between the carrot and the beet root, while Dr. Maclean succeeded in engrafting, on a red beet, a scion of the white Silesian variety of the same species. In all these cases, even in the most successful grafts, the amount of adhesion is very slight; the union in no degree warrants the term fusion, it is little but simple contact of similar tissues, while new growing matter is formed all round the cut surfaces, so that the latter become gradually imbedded in the newly formed matter.

Synophty or adhesion of the embryo.—This often occurs partially in the embryo plants of the common mistleto (Viscum), but is not of common occurrence in other plants, even in such cases as the orange (Citrus), the Cycadeae, Coniferae, &c., where there is frequently more than one embryo in the seed. Alphonse De Candolle has described and figured an instance of the kind in Euphorbia helioscopia, wherein two embryo plants were completely grafted together throughout the whole length of their axes, leaving merely the four cotyledons separate. A similar adnation has been observed by the same botanist in Lepidium sativum and Sinapis ramosa, as well as in other plants.[64] I have met with corresponding instances in Antirrhinum majus and in Crataegus oxyacantha, in the latter case complicated with the partial atrophy of one of the four cotyledons. It is necessary to distinguish between such cases and the fallacious appearances arising from a division of the cotyledons. M. Morren has figured and described the union of two roots of carrot (Daucus), which were also spirally twisted. He attributes this union to the blending of two radicles, and applies the term "rhizocollesy" to this union of the roots.[65] Mr. Thwaites cites a case wherein two embryos were contained in one seed in a Fuchsia, and had become adherent. What is still more remarkable, the two embryos were different, a circumstance attributable to their hybrid origin, the seed containing them being the result of the fertilisation of Fuchsia coccinea (quere F. magellanica?) by the pollen of F. fulgens.

FOOTNOTES:

[30] Wydler, 'Flora,' 1852, p. 737, tab. ix.

[31] 'El. Ter. Veg.,' p. 254.

[32] 'Bull. Soc. Bot. Fr.,' 1857, p. 451.

[33] 'Bull. Acad. Belg.,' vol. xix, part ii, p. 335.

[34] 'Bull. Soc. Bot. Fr.,' 1860, p. 25.

[35] 'Bull. Soc. Bot. Fr.,' 1861, p. 147.

[36] 'Bull. Acad. Belg.,' vol. xviii, part ii, p. 498.

[37] See also Prillieux, 'Bull. Soc. Bot. Fr.,' 1861, p. 195.

[38] 'Mem. Acad. Toulouse,' 5th Series, vol. iii.

[39] Linnaea, vol. ii. p. 607.

[40] 'Journal Roy. Hort. Soc.,' new ser., vol. i. 1866, p. 200.

[41] 'Bull. Soc. Bot. Fr.,' 1861, p. 159.

[42] Ibid., 1859, p. 467.

[43] 'Flora,' 1858, p. 65, tab. ii.

[44] C. Morren. 'Bull. Acad. Belg.,' vol. xv (Fuchsia, p. 89); vol. xviii, p. 591. (Lobelia, p. 142); vol. xix, p. 352; vol. xx, p. 4.

[45] 'Bull. Soc. Bot. Fr.,' vol. vii, p. 625.

[46] Cramer, 'Bildungsabweichungen,' p. 56, tab. vii, fig. 10, figures a case wherein the two central flowers of the capitulum of Centaurea Jacea were united together.

[47] 'Bull. Bot.' tab. iii, figs. 4-6.

[48] 'Mem. greffe Ann. Science Nat.,' ser. i, t. xxiv, p. 334.

[49] "Mespilus portentosa." Poit. et Turp., 'Pomol. Franc.,' liv, xxxi, p. 202, pl. 202.

[50] Duchesne, 'Hist. Nat. Frais.,' p. 79.

[51] De Cand., 'Phys. Veget.,' tom. ii, p. 781.

[52] Sched. de monstr. plant. 'Act. Helv.,' tab. i, fig. 8.

[53] 'Mem. greffe,' loc. cit., tab. xxiv, p. 334.

[54] 'Bull. Soc. Bot. Franc.,' 8, pp. 73 and 351, tab. ii; and Roese. 'Bot. Zeit.,' x, p. 410.

[55] Nymphaea lutea, AEsculus Hippocastanum, &c. See Moquin, 'El. Ter. Veg.,' p. 277.

[56] C. Martins, 'Promenade Botanique,' p. 8.

[57] 'Ann. Sc. Nat.,' t. xix, 1843, p. 141, tab. iv.

[58] 'Ann. Nat. Hist.,' ser. 2, vol. ix, tab. xvi. 'Phytologist,' 1857. p. 352, &c.

[59] Quoted from the 'Revue Hortic.' in 'Gard. Chron.,' 1866, p. 386.

[60] Senebier, 'Phys Veget.,' t. iv, p. 426. The same author also cites Romer as having found two plants of Ranunculus, from the stem of which emerged a daisy. As it is not an uncommon practice to stick a daisy on a buttercup, it is to be hoped no hoax was played off on M. Romer.

[61] 'El. Ter. Veg.,' p. 289.

[62] An instance of this kind is cited in Dr. Robson's memoir of the late Charles Waterton, from which it appears that two trees, a spruce fir and an elm, were originally planted side by side, and had been annually twisted round each other, so that they had in places grown one into the other, with the result of stunting the growth of both trees, thus illustrating, according to the opinion of the eccentric naturalist above cited, the incongruous union of Church and State!

[63] See Daubeny, 'Lectures on Roman Husbandry,' p. 156.

[64] A. P. De Candolle, 'Organ Veget.,' t. ii, p. 72, tab. liv, fig. 1.

[65] 'Bull. Acad. Belg.,' t. xx, part i, 1852, p. 43.



PART II.

INDEPENDENCE OR SEPARATION OF ORGANS.

Under this head are included all those instances wherein organs usually entire, or more or less united, are, or appear to be, split or disunited. It thus includes such cases as the division of an ordinarily entire leaf into a lobed or partite one, as well as those characterised by the separation of organs usually joined together. Union, as has been stated in a previous chapter, is the result either of persistent integrity or of a junction of originally separate organs, after their formation; so in like manner, the separation or disjunction of parts may arise from the absence of that process of union which is habitual in some cases, or from an actual bona fide separation of parts originally united together. In the former case, the isolation of parts arises from arrest of development, while in the latter it is due rather to luxuriant growth. A knowledge, as well of the ordinary as of the unusual course, of development in any particular flower is thus required in order to ascertain with accuracy the true nature of the separation of parts. The late Professor Morren[66] proposed the general term Monosy ([Greek: monosis]) for all these cases of abnormal isolation, subdividing the group into two, as follows—1, Adesmy ([Greek: a-desmos]), including those cases where the separation is congenital; and 2, Dialysis ([Greek: dialyo]), comprising those instances where the isolation is truly a result of the separation of parts previously joined together. Adesmy, moreover, was by the Belgian savant said to be homologous when it occurred between members of the same whorl, e.g. between the sepals of an ordinary monosepalous calyx, or heterologous when the separation took place between members of different whorls, as when the calyx is detached from the ovary, &c. The former case would thus be the converse of cohesion, the latter of adhesion.

To the adoption of these words there is this great objection, that we can but rarely, in the present state of our knowledge, tell in which group any particular illustration should be placed.

The terms adopted in the present work are, for the most part, not necessarily intended to convey any idea as to the organogenetic history of the parts affected. Where a single organ, that is usually entire, becomes divided the term Fission is used; in cases where parts of the same whorl become isolated, the word Dialysis is employed, and in the same sense in which it is generally used by descriptive botanists, and where the various whorls become detached one from the other, the occurrence is distinguished by the application of the term Solution.

FOOTNOTES:

[66] 'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315.



CHAPTER I.

FISSION.

When an organ becomes divided it receives at the hands of descriptive botanists the appellations cleft, partite, or sect, according to the depth of the division; hence in considering the teratological instances of this nature, the term fission has suggested itself as an appropriate one to be applied to the subdivision of an habitually entire or undivided organ. It thus corresponds pretty nearly in its application with the term Chorisis or "dedoublement," or with the "disjonctions qui divisent les organes" of Moquin-Tandon.[67] It is usually, but not always, a concomitant with hypertrophy, and dependent on luxuriance of growth.

It must be understood therefore that the term, as generally applied, does not so much indicate the cleavage of a persistent organ, as it does the formation and development of two or more growing points instead of one, whence results a branching or forking (di-tri-chotomy) of the affected organ. In some instances it seems rather to be due to the relative deficiency of cellular, as contrasted with fibro-vascular tissue.

Fission of axile organs.—This condition is scarcely to be distinguished from multiplication of the axile organs (which see). A little attention, however, will generally show whether the unusual number of branches is a consequence of the development of a large number of distinct shoots, as happens, for instance, when a tree is pollarded, or of a division of one. M. Fournier[68] gives as an illustration the case of a specimen of Ruscus aculeatus in which there occurred a division of the foliaceous branches into two segments, reaching as far as the insertion of the flower, but no further. He also mentions lateral cleavage effected by a notching of the margin, the notch being anterior to the flowers and always directed towards their insertion. In the allied genus Danae, Webb, 'Phyt. Canar.,' p. 320, describes the fascicles of flowers as in "crenulis brevibus ad marginem ramulorum dispositis." Sometimes, on the other hand, Danae has a fascicle of flowers inserted on the middle of the upper surface, as in Ruscus. Wigand mentions an instance in Digitalis lutea, where the upper part of the stem was divided into six or seven racemes; possibly this was a case of fasciation, but such a division of the inflorescence is by no means uncommon in the spicate species of Veronica. I have also seen it in Plantago lanceolata, Reseda luteola, Campanula medium, Epacris impressa, and a bifurcation of the axis of the spikelet within the outer glumes in Lolium perenne[69] and Anthoxanthum odoratum. In the Kew Museum is preserved a cone of Abies excelsa,[70] dividing into two divisions, each bearing bracts and scales. A similar thing frequently occurs in the male catkins of Cedrus Libani (fig. 25).



This subdivision of axial organs is not unfrequently the result of some injury or mutilation, thus Duval Jouve alludes to the frequency with which branched stems are produced in the various species of Equisetum, as a consequence of injuries to the main stem, but this is rather to be considered as a multiplication of parts than as a subdivision of one.



Fission of foliar organs.—Many leaves exhibit constantly the process of fission, such as the Salisburia adiantifolia, and which is due perhaps as much to the absence or relatively small proportion of cellular as compared with vascular tissue, as to absolute fission. In the same way we have laciniated leaves of the Persian lilac, Syringa persica, and Moquin mentions instances in a species of Mercurialis in which the leaves were deeply slashed. In Chenopodium Quinoa the leaves were so numerous and the clefts so deep, that the species was hardly recognisable, while on a branch of Rhus Cotinus observed by De Candolle the lobes were so narrow and so fine as to give the plant the aspect of an Umbellifer. Wigand ('Flora,' 1856, p. 706) speaks of the leaves of Dipsacus fullonum with bi-partite leaves; Moquin mentions the occurrence of a leaf of an oleander bi-lobed at the summit, so as to give the appearance of a fusion of two leaves. Steinheil has recorded an instance in Scabiosa atropurpurea in which one of the stem leaves presented the following peculiarities. It was simple below, but divided above into two equal lobes, provided each with a median nerve.[71] Steinheil has also recorded a Cerastium in which one of the leaves was provided with two midribs; above this leaf was a group of ternate leaves. I have seen similar instances in the common Elm, Ulmus campestris, and also in the common nettle, Urtica dioica, the leaves of which latter thus resembled those of Urtica biloba, which are habitually bilobed at the summit. M. Clos[72] mentions an instance where the terminal leaf and first bract of Orchis sambucina were divided into two segments. The same author also mentions the leaves of Anemiopsis californica, which were divided in their upper halves each into two lobes—also leaves of a lentil springing from a fasciated stem and completely divided into two segments, but with only a single bud in the axil. The axillary branches in like manner showed traces of cleavage. Fig. 26 represents a case of this kind in Lamium album, conjoined with suppression of the flowers on one side of the stem. I have also in my herbarium a leaf of Arum maculatum, with a stalk single at the base, but dividing into two separate stalks, each bearing a hastate lamina, the form of which is so perfect that were it not from the venation of the sheath it would be considered that there was here a union of two leaves rather than a bifurcation of one. A garden Pelargonium presented the same appearance.



Fern fronds are particularly liable to this kind of subdivision, and they exhibit it in almost every degree, from a simple bifurcation of the frond to the formation of large tufts of small lobes all formed on the same plan by the repeated forking of the pinnules. These may be considered as cases of hypertrophy.

Moquin-Tandon, at a meeting of the Botanical Society of France (April 3rd, 1858) exhibited a leaf of Cerasus Lauro-Cerasus divided in such a manner as to resemble a leaf of Citrus or of Phyllarthron. In this case, therefore, the disunion must have taken place laterally, and not from apex towards base, as is most common. The leaves of the common horse-radish, Cochlearia Armoracia, are very subject to this pinnated subdivision of the margin, and numerous other illustrations might be given.



A. Braun describes a singular case in a leaf of Irina glabra wherein the blade of the leaf on one side was deeply and irregularly laciniated, the other side remaining entire. (Verhandl., d. 35, Naturforscherversammlung, tab. 3.) Laciniate varieties of plants are of frequent occurrence in gardens where they are often cultivated for their beauty or singularity; thus, there are laciniated alders, fern-leaved beeches and limes, oak-leaved laburnums, &c. A list of several of these is subjoined. A similar fission takes place constantly in the cotyledons of some plants, sometimes, as in Coniferae, to such an extent as to give an appearance as if there were several cotyledons.[73]

It is not always easy to recognise, at a first glance, whether the division be the result of disunion or of an incomplete union of two leaves, but we may be guided by the number of leaves in the cycle or the whorl. The number is complete in cases of partial disjunction, while in cases of fusion it is incomplete. Again, in instances of disjunction, there is only one point of origin, but, when two leaves are grafted together, two such points may generally be detected at the base of the leaf, or a transverse section of the leaf-stalk will show indications of fusion. The number and position of the midribs will also serve as a guide, as in cases of fusion there are generally two or more midribs, according to the number of fused leaves; but as Moquin well remarks, this latter character cannot be always depended upon, for the median nerve may divide without any corresponding separation of the cellular portions of the leaf. The author just quoted cites examples of this kind in Cardamine pratensis, Hedera Helix, Plantago major, Geranium nodosum.

The following list of plants commonly producing leaves that are cleft or divided, to a greater extent than is usual in the species, is mainly taken from one given by Schlechtendal, 'Bot. Zeit.,' 1844, p. 441, with additions from other sources. The ! indicates that the author has himself met with the deviation in question. Many are cultivated as garden varieties under the names here given.

Trollius europaeus dissectus. Chelidonium majus laciniatum! Glaucium luteum. Brassica oleracea! Tilia parvifolia laciniata. asplenifolia! Acer platanoides laciniatum. crispum. AEsculus Hippocastanum incisum! asplenifolium. Vitis vinifera apiifolia! laciniosa. Ilex Aquifolium! Rhus Toxicodendron quercifolium. Cotinus. Ervum Lens. Cytisus Laburnum quercifolium! incisum. Rubus fraticosus laciniatus! Pyrcis communis. Cerasus Lauro-cerasus. Apium graveolens! Pimpinella magna. Saxifraga. Crataegus Oxyacantha laciniata. quercifolia! Ribes nigrum. Sambucus nigra laciniata! racemosa laciniata. Dipsacus fullonum. Scabiosa atropurpurea! Symphoricarpus racemosus. Helianthus sp.! Lonicera Periclymenum quercifolia! Syringa persica laciniata! Syringa vulgaris! Nerium Oleander! Lamium purpureum. album! Salvia officinalis. Solanum Dulcamara! Fraxinus excelsior crispa. Veronica austriaca. Polemonium caeruleum. Juglans regia laciniata! heterophylla. filicifolia. Anemiopsis californica. Chenopodium Quinoa. Ulmus americana incisa. Fagus sylvatica heterophylla! laciniata! aspleniifolia! incisa. salicifolia! Mercurialis perennis. Urtica dioica. Quercus Cerris laciniata! pubescens filicina. Betula populifolia laciniata. alba dalecarlica. Alnus incana laciniata! glutinosa laciniata! quercifolia. oxyacanthifolia. Corylus Avellana heterophylla! laciniata! urticifolia. Carpinus Betulus incisa! quercifolia. heterophylla. Castanea vesca heterophylla. quercifolia. incisa. Populus alba acerifolia. palmata. quercifolia. balsamifera. Orchis sambucina. Arum maculatum. Filices sp. pl.

See also Schlechtendal, 'Bot. Zeit.,' tom. xiii, p. 823. A. Braun, loc. supra citat. For Ferns too numerous for insertion, see Moore, 'Nature-Printed Ferns,' 8vo ed., 2 vols. Clos, 'Mem. Acad. Toulouse,' 1862, p. 51.

Fission of the petals, &c.—The floral leaves are subject to a similar process of cleavage to that which has just been mentioned as taking place in the leaves. This, indeed, occurs very often as a normal occurrence as in the petals of mignonette (Reseda), or those of Alsine media and many other plants. Here, however, we have only to allude to those instances in which the cleavage occurs in flowers whose sepals or petals are usually entire. Under this category Moquin mentions a petal of Brassica oleracea completely split into two. Linne in his 'Flora Lapponica' (pp. 145 and 164) mentions quadrifid petals of Lychnis dioica, and much divided petals of Rubus arcticus. Among other plants subject to this division of sepals or petals may be mentioned as having come within the writer's personal observation, Ranunculus Lingua, R. acris, Papaver somniferum, and others of this genus, Saponaria sp., Dianthus, Narcissus, &c.

In some of the garden varieties of Cyclamen the corolla looks at first sight as if double, and the plan of the flower is oblong or elliptical, instead of circular. In these flowers each lobe of the corolla is divided almost to the base into two lobes, so that there appear to be ten lobes to the corolla instead of five, as usual. The stamens are normal in form and number in these flowers.

In the paroquet tulips of gardeners the segments of the perianth are deeply and irregularly gashed, the segments occasionally becoming rolled up and their margins coherent so as to form little tubular spurs. I have also noticed the segments of the perianth in Crocus and Colchicum deeply cleft, so much so sometimes, as to equal in this particular the stigmas. In the flowers of a species of Oncidium, communicated to me by Mr. Currey, the lip was divided into three segments perfectly distinct one from the other, but confluent with the column; the two side pieces had callosities at the upper edge close to the base, the central piece had a similar wartlike process in its centre. In these flowers the ovary, the stigma, and the anther were all in a rudimentary condition. Some verbenas raised by Mr. Wills offer a curious illustration of this condition. It will be remembered that some of the lobes or petals of a verbena are normally divided at the base to a slight degree, but in the flowers in question this is carried to such an extent that the enlarged lobes are pushed into the centre of the flower and simulate, at a first glance, a distinct and separate organ, though in reality it is but an enlargement of what occurs normally.[74]



Moquin mentions having seen the stamens of Matthiola incana and Silene conica completely divided, each section bearing half an anther, exactly as happens in Polygalaceae. In tulips and lilies the same author mentions division of the anther only, the filament remaining entire, as happens naturally in many species of Vaccinium.

A division of the individual carpels occurs very frequently when those organs become more or less leafy, as in Trifolium repens, and other plants to be hereafter mentioned.

The instances given in this chapter have all been cases wherein the division or the accessory growth has taken place in one plane only and that plane the same as that of the affected organ, but there are other examples, probably equally due to fissiparous division, where the new growth is either parallel to, or even at angle with the primary organ. Of such nature are some of those instances wherein two leaves appear to be placed back to back. These partake of the nature of excrescences or of exaggerated developments, and hence will be more fully treated of under the head of hypertrophy. It must be remembered that in some of these cases the fission may be a resumption of characters proper to the species under natural conditions, but lost by cultivation or otherwise. Thus, Mr. Buckman accounts for "finger-and-toe" in root-crops on the principle of reversion to the wild form.

FOOTNOTES:

[67] Loc. cit., p. 295.

[68] 'Bull. Soc. Bot. France,' 1857, p. 758.

[69] Masters, 'Jourl. Linn. Soc.,' vol. vii, p. 121.

[70] Cramer, 'Bildungsabweichungen,' p. 4, tab. vi, fig. 4, figures a case of the same kind in Pinus Cembra.

[71] 'Ann. des Science Nat.,' 2nd series, t. iv, p. 147, tab. v, figs. 3 and 4.

[72] 'Mem. Acad. Scien. Toulouse,' 5th series, vol. iii.

[73] Duchartre, 'Ann. Sc. Nat.,' 3rd series, 1848, vol. x, p. 207.

[74] Masters, 'Rep. Bot. Congress,' London, 1866, p. 136, tab. 7, f. 15, 16.



CHAPTER II.

DIALYSIS.

This term is here made use of in the same sense as in descriptive botany, to indicate the isolation of parts of the same whorl; it is thus the opposite of cohesion. Morren, as has been previously stated, employed the word in a different sense, while Moquin-Tandon[75] included cases of this description under the category of "Disjonctions qui isolent les organes."

Dialysis, as here understood, may be the result of an arrest of development, in consequence of which parts that under ordinary circumstances would become fused, do not do so; or, on the other hand, it may be the result of an actual separation between parts primitively undivided. As it is not possible in every case to distinguish between the effects of these two diverse causes, no attempt is here made to do so.

Dialysis of the margins of individual foliar organs.—In cases where the leaf or leaf-like organ is ordinarily tubular or horn-like in form, owing to the cohesion of its edges, it may happen either from lack of union or from actual separation of the previously united edges, that the tubular shape is replaced by the ordinary flattened expansion. Thus, in Eranthis hyemalis, wherein the petals (nectaries) are tubular and the sepals flat, I have met with numerous instances of transition from the one form to the other, as shown in fig. 9, p. 24.

It is, however, in the carpels that this separation occurs most frequently. When these organs appear under the guise of leaves, as they often do, their margins are disunited, so that the carpel becomes flat or open. This happens in the strawberry (Fragaria), the columbine (Aquilegia), in Trifolium repens, Ranunculus Ficaria, &c.[76]

Dialysis of the parts of the same whorl:—calyx.—The separation of an ordinarily coherent series into its constituent parts is necessarily of more common occurrence than the foregoing. As here understood, it is the precise converse of cohesion, and it may be represented diagrammatically by a dotted line above the letters denoting the sepals, petals, &c. When this change happens in the calyx we have the gamosepalous condition replaced by the polysepalous one, as thus represented:

............. S S S S S instead of ___ S S S S S

as in a calyx of five coherent sepals.

Detachment of this kind occurs not unfrequently, as in Primula vulgaris, Trifolium repens, &c. In Rosaceae and Pomaceae this separation of the calyx is of the more moment, as it has reference to the structure of the inferior ovary, as will be more fully mentioned hereafter. Here, however, a case recorded by M. J. E. Planchon may be alluded to[77] wherein a quince fruit (Cydonia) was surmounted by five leaves, the surface of the pome being marked by as many prominences, which apparently corresponded to the five stalks of the calycine leaves. In this specimen, then, the inferior position of the ovary appeared to be not so much due to an expansion of the fruit stalk, as to the fusion of the hypertrophied stalks of the sepals. Some of the malformations among Cucurbits point to a similar structure. It is probable that in many of these cases the so-called inferior ovary is partly axial partly foliar, i.e., sepaline, and partly carpellary in its nature.

Dialysis of the sepals in calyces that are usually gamosepalous has been most frequently observed in Rosaceae, Pomaceae, Umbelliferae, less commonly in Leguminosae, also in the following genera:—Primula, Symphytum, Gentiana, Campanula, &c.



Dialysis of the corolla is likewise of frequent occurrence, either partially or to such an extent as to render the corolla truly polypetalous. Among Labiatae the upper lip of the corolla may be often met with partially cleft, as it is constantly in Phlomis biloba, or more markedly among the Lobeliaceae.

In the Compositae, a similar separation of the petals is not infrequent, thus showing frequent transitional stages between the labiatifloral and tubulifloral divisions respectively. The ligulate corollas also may often be found in Chrysanthemums, Dahlias, &c., more or less deeply divided into their component parts.

A more complete separation occurs not unfrequently in Campanula, Rhododendron, Phlox, &c. Figs. 30 and 31 illustrate dialysis of the corolla; the first in Correa, the second in Campanula.



In the last-named genus, C. rotundifolia has been found with polypetalous flowers in a wild state in the mountains of Canton Neufchatel, Switzerland, and gave rise to the creation of a new genus. This form is now introduced into gardens.

It must be remembered that in some genera, where this separation of the petals has been met with, there are species in which a similar isolation occurs normally, as in Rhododendron. R. linearilobum, a Japanese species, offers a good illustration of this.

The following list contains the names of the genera in which this separation of the petals of an ordinarily gamopetalous flower takes place most frequently.

Correa. Campanula! sp. pl. Polemonium. Phlox! Coboea! Rhododendron! Erica! Rhodora. Azalea! Compositae! sp. pl. Lonicera! Convolvulus! Pharbitis. Antirrhinum! Verbascum! Mimulus. Digitalis! Orobanche. Solanum. Nicotiana. Gentiana! Anagallis. Primula! Lamium! Convallaria! Lilium! Colchicum! &c. &c.

This list does not include those very numerous cases in which this change is associated with more or less complete frondescence or leafy condition of the petals.

Dialysis of the stamens.—A similar isolation of the stamens occurs occasionally; for instance, when Mallows (Malvaceae) become double, one of the first stages of the process is often the disjunction of the stamens, and a similar dissociation occurs in Leguminosae and Compositae, as in Tragopogon, as related by Kirschleger, in Hypochaeris by Wigand, and in Coreopsis by Schlechtendal.

Dialysis of the carpels.—In the case of the carpels this disunion is more frequent than in the stamens. M. Seringe[78] figures carpels of Diplotaxis tenuifolia more or less completely separated one from the other; indeed, this separation is very common amongst Cruciferae and Umbelliferae.

Generally speaking, the disunion is complicated with frondescence—but not always so. I have, in my herbarium, specimens of Convallaria majalis, Commelyna sp., and of Lilium auratum, in all of which the three carpels are completely disjoined, and present three styles, three stigmas, &c., without any other change. Engelmann[79] speaks of three classes of this malformation. 1st, that in which the carpels separate one from the other without opening, as in the lily just alluded to; 2nd, that in which the ovary remains closed, but loses its internal partitions, as in a case mentioned by Moquin in Stachys sylvatica, in which, owing to imperfect disjunction, the two bi-lobed carpels were changed into a nearly one-celled capsule;[80] and 3rd, those cases in which the carpels are open and foliaceous.



Disjunction is more frequent in dry fruits than in fleshy ones. In the latter instance it happens at an early stage of existence, and the pericarp becomes more or less leafy, losing its faculty of becoming fleshy, as in Prunus Cerasus and Amygdalus persica; nevertheless, fleshy fruits sometimes become disunited. I have seen a case similar to that mentioned by M. Alphonse de Candolle in Solanum esculentum, in which the pericarp became ruptured, and the placentas protruded. A like occurrence has also been observed in a species of Melastoma.[81] This is analogous to what happens in Caulophyllum and Slateria. Disjunction of the carpels is not rare in oranges. Sometimes this takes place regularly, at other times irregularly; occasionally in such a manner as to give the appearance of a hand and fingers to the fruit. Of one of these, Ferrari,[82] in the curious volume below cited, speaks thus: "Arbor profusissima, quia dat utraque manu; imo quia vere manus dat in poma conversis; utque magis munifica sit poma ipsa convertit in manus."

M. Duchartre[83] mentions a semi-double flower of orange with eight to ten distinct carpels in a whorl, and occasionally several whorls one above another. De Candolle[84] considers the rind of the orange as a production from the receptacle, and this view is confirmed by the specimens of Duchartre, in which the carpels were quite naked or had a common envelope truncated, and open above to allow of the passage of the styles and stigmas.



It frequently happens in conjunction with this separation of the carpels one from the other, that a lack of union manifests itself between the margins of the individual carpels themselves. Very numerous cases of this kind have been recorded, and the double tulips of gardens may be referred to as showing this condition very frequently. In connection with this detachment of the carpels, a change in the mode of placentation is often to be observed, or two or more kinds may be seen in the same pistil, as in double-flowered saponarias, many Crucifers, &c., as alluded to under the head of displacements of the placenta.

FOOTNOTES:

[75] Loc. cit., p. 298.

[76] Masters in Seemann's 'Journal of Botany,' 1867, p. 158.

[77] Bull. Soc. Bot. France,' t. xiii, 1866, p. 234.

[78] 'Bull. Bot.,' pl. i, figs. 8-12.

[79] 'De Anthol.,' p. 37.

[80] Moquin, loc. cit., p. 305.

[81] 'Neue Denkschr. der Allg. Schweiz. Gesell.,' band v, pl. ii. p. 5.

[82] 'Hesperides,' auctore Ferrario. Rome, 1646, fig. 415, pp. 213 and 215. See also Michel, 'Traite du Citronnier.'

[83] 'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294.

[84] 'Org. Veget.,' vol. ii., p. 41.



CHAPTER III.

SOLUTION.

The isolation or separation of different whorls that are ordinarily adherent together is by no means of rare occurrence. Were it not that the isolation is often congenital, the word detachment would be an expressive one to apply to these cases, but as the change in question occurs quite as often from a want of union, an arrest or stasis of development, as from a bona fide separation, the word solution seems to be, on the whole, the best. It corresponds in application to the word liber (calyx liber, &c.), in general use by descriptive botanists. As here employed, the term nearly corresponds with the "adesmie heterologue" of Morren. Moquin Tandon does not make any special subdivision for the class of cases here grouped together, but places them all under "Disjonctions qui isolent les organes." It seems, however, desirable to have a separate word to express the converse condition of adhesion, and for this purpose the term solution, as above stated, is here employed. Diagrammatically, the condition may be expressed by placing a dotted line at the side of the letters thus:

: s s s s s : : c c c c c :

would indicate the disjunction of the sepals from the carpels (c), in contradistinction to adhesion, which may be represented by the unbroken line thus:

s s s s s c c c c c

Solution of the calyx from the ovary.—Of all the instances of adhesion which take place under ordinary circumstances, that between the calyx and the ovary is perhaps the most common. The calyx adhaerens or superus is a structural characteristic to which all botanists attach considerable importance; so that when exceptional cases occur in which the calyx becomes detached from the ovary, becomes, that is, inferus or liber, a proportionate degree of interest attaches to the irregularity. It is not within the scope of the present work to inquire whether this detachment be real or merely apparent, arising from a want of union between parts ordinarily united together. This point must be left to the organogenists to decide in each particular case. So also the question as to what share, if any, the expanded and dilated flower-stalk may take in what are usually called inferior ovaries, can be here only incidentally touched upon.

Among Rosaceae, the change in question is very common, especially in conjunction with an elongation of the axis of the flower (apostasis) and with prolification, though it is by no means always co-existent with these malformations. When this alteration in the apparent relative position of calyx and carpels occurs in roses (Rosa) the appearances are generally such as to indicate that the "hip" of the rose is a dilatation of the peduncle, continuous above with the coherent bases of the sepals; this inference seems also to be borne out by what happens in the Pomaceae. In some cases in this sub-order, the calyx becomes detached from the carpels, so that the latter organs become more or less "superior," and distinct one from the other. This happens constantly in the double-flowered thorn, Crataegus Oxyacantha, in some blossoms of which the hollowed end of the peduncle still invests the base of the carpels, leaving the upper portions detached. In apples flowers are occasionally met with of greater size than usual and on longer stalks, so that the whole looks more like a rose than an apple blossom. In these cases it will usually be found that the calyx consists of distinct sepals, without a trace of the ordinary swelling beneath the flower. The petals are often more numerous than usual; the stamens variously changed, and the carpels sometimes absent; at other times, as in the instance figured in the adjacent woodcuts, figs. 36, 37, consisting of separate, superior ovaries, sometimes destitute of ovules, or, at other times, having two of these bodies.[85]



This condition accords precisely with the account of the development of the flowers in Pomaceae as given by Payer, Caspary, and others, so that the flowers above described would owe their deficiency of the swollen receptacle to an arrest of development. M. Germain de Saint Pierre, among other malformations of the rose, presented to the Botanical Society of France in 1854[86] two specimens which are of special interest as relating to this contested point. In the one, the swollen portion beneath the flower was surmounted by five perfect leaves, as, indeed, is not infrequent in such malformations; here, then, the calyx could have had little or no share in the production of the swelling in question. In the other, the swollen portion was actually above the insertion of the sepals here represented by five perfect leaves.



On the other hand, M. Planchon's specimen of the Quince before alluded to, not to mention other instances, tends to show that the bases of the sepals do sometimes enter into the composition of the pome. And, indeed, in many of these cases it would be impossible to say where the axial or receptacular portion ended, and the foliar portion began. As both from normal organogeny as well as from unusual conformation contradictory inferences may be drawn, it would obviously be unsafe to attempt the explanation of the so-called calyx-tube in general from any particular instances; so far as Rosaceae are concerned, there is so much variation in the relative position of calyx and carpels under ordinary circumstances, that it is no matter for surprise that similar diversities should exist in teratological cases. A similar remark will apply to Saxifragaceae, Cucurbitaceae, Myrtaceae, Bruniaceae, Rubiaceae, and other families of like conformation.



In Umbelliferae, a detachment of the calyx from the ovaries frequently occurs, sometimes without any other change; at other times attended by more serious alterations. So far as can be judged from exceptional occurrences of this kind, it would appear that in this order the axis or flower-stalk does not, in any material degree, enter into the composition of the fruit.

In the Rubiaceous genus Bikkhia, as mentioned by Duchartre, the ovary is completely inferior, but when the fruit arrives at maturity four small leaves are detached from its surface which had previously adhered to it, and which it seems reasonable to consider as the sepals.

In Campanulaceae a similar separation of calyx from the ovary may be occasionally met with. On the other hand, the occasional formation of a leaf on the inferior ovary of those plants would indicate the axial nature of the fruit. In Campanumaea and Cyclodon the calyx is inferior, while the corolla is superior. In the last-named genus this peculiarity "is carried to the highest degree, the sepals being, in C. parviflorum, placed on the peduncle of the flower far removed from the base of the corolla and ovary, whilst in C. truncatum and in Campanumaea they adhere to the base of the tube of the corolla."[87] In this order, then, as in Saxifragaceae, Bruniaceae, &c., no hasty conclusion should be drawn as to the nature of the fruit. In Brunia microphylla the ovary is superior, enclosed within but not adnate to the cup-like calyx, to which latter, however, the petals and stamens are attached.

In Onagraceae (Jussieua), as also in Cactaceae (Opuntia), buds have been observed on the surface and edges of the inferior ovary. Indeed, in the former genus, they have been produced artificially, but as buds may be formed on foliar as well as on axial organs, the fact cannot be made great use of in support either of the foliar or axial nature of the inferior ovary. In Epilobium, I have met with four perfect leaves at the summit of the ovary, in the place usually occupied by the sepals. This would also favour the notion that the axis entered into the constitution of the fruit in this genus.

Mr. B. Clarke, in his 'New Arrangement of Phanerogamous Plants,' p. 4, cites a case wherein the perianth was completely detached from the surface of the ovary in Cannabis sativa.

It must be borne in mind that some of the recorded instances of change in the relative position of the calyx and pistil ought more properly to be referred to a substitution of carpels for stamens, as in Begonia, Fuchsia, &c. Among Cucurbitaceae, examples have been recorded, both of the detachment of the calyx from the ovary,[88] and of the partial conversion of some of the anthers of the male flower to carpels.

The very singular mode of germination of Sechium edule in which the fruit, instead of rotting, becomes thickened into a kind of rhizome or tuber, is a fact that should not be overlooked in investigating the true nature of the fruit in this order.

The following are the genera in which the change has been most frequently observed:

*Rosa! *Pyrus! *Crataegus! *Daucus! Pastinaca. Torilis. Apium. OEnanthe! Heracleum, Athamanta. Selinum. Carum. Imperatoria. Rudbeckia! *Campanula! Lonicera! Cucumis! Cannabis.

Solution of the stamens from the petals.—A separation of the stamens from the petals in flowers, wherein those organs are usually adherent one to the other does not often occur unattended by other changes. It has been observed in Cobaea scandens (Turpin), in Antirrhinum majus, and in many double flowers.

Partial detachment of the stamens from the styles occurs frequently in semi-double flowers of Orchis.[89]

FOOTNOTES:

[85] 'Gard. Chron.,' 1865, p. 554; 1867, p. 599.

[86] 'Bull. Soc. Bot. Fr.' 1854, p. 303.

[87] Hook et Thoms, 'Praecurs. ad Flor. Ind.,' Journ. Linn. Soc., vol. ii, 1858, p. 6.

[88] Lindley, 'Veget. Kingd.,' p. 315.

[89] Masters, 'Journal of Linnean Society,' 1866, vol. viii, p. 207. On the subject of this chapter the reader should also consult Moquin-Tandon, 1. c., p. 298. Engelmann, 'De Antholysi,' p. 37, tab. v. C. Morren, 'Bull. Acad. Belg.,' xix, part 3, p. 318. Cramer, 'Bildungsabweichungen,' p. 64. Fleischer, 'Missbild. Cultur. Pflanzen.' As to the nature of inferior ovaries, see also Payer, 'Bull. Soc. Bot. Fr.' i, 1854, p. 283. Germain de Saint Pierre, ibid., p. 302. Caspary, 'Bull. Soc. Bot. Fr.,' t. vi, 1859, p. 235. Schleiden, 'Principles of Botany,' English translation, p. 368. Duchartre, 'Elements de Botanique,' p. 574. Le Maout et Decaisne, 'Traite general de Botanique,' p. 57. Bentham, 'Journ. Linn. Soc.,' vol. x, p. 104 (Structure of Myrtaceae), and other treatises on Organography.



PART III.

ALTERATIONS OF POSITION.

Necessarily connected with changes in the arrangement of organs are similar alterations in their position; so closely, indeed, that but for convenience sake, it would be unnecessary to treat them separately. There are, however, some anomalous developments affecting the relative position of organs that could hardly be treated of under any of the preceding paragraphs. There are, also, certain rare instances where an organ is not so much displaced as misplaced; that is to say, it is developed on or from a portion of the plant, which under usual circumstances does not produce such an organ. In the former instance, the altered position is due to or coexistent with other changes, but in the latter case the new growth may spring from organs otherwise in nowise different from ordinary. The word Displacement is here used to signify the unusual position of an organ; while Heterotaxy may serve to include those cases where a new growth makes its appearance in an unwonted situation, as, for instance, a leaf-bud on a root, &c. Prolification is also included under this heading, the unusual position of the buds in these cases being of graver import than the mere increase in number. Alterations in the position of the sexual organs are spoken of under the head of Heterogamy.



CHAPTER I.

DISPLACEMENT.

Real or apparent displacement of organs from their usual position is an almost necessary consequence of, or is, at least, coexistent with a large number of teratological phenomena. It is obvious that abnormal unions or disunions, suppressions, hypertrophies, &c., are very liable to bring about or to be accompanied with changes in the position, either of the parts directly affected or of adjoining organs.

In this place, then, it is merely necessary to allude to some of the more important displacements, and to refer for further details to the sections relating to those irregularities of growth on which the displacement depends.

Displacement of bulbs.—I owe to the kindness of Mr. James Salter a tulip bulb which had been dug up after flowering, and from the base of which were suspended several small bulbs; and I have since seen another specimen showing the same unusual arrangement. The explanation of these formations seems to be that they correspond to the bulbils ordinarily found in the axils of the scales of the parent organ, and which, in some way or another, have been displaced and thrust into the ground. Professor de Vriese figures something of the same kind in Ixia carminosa.[90]

Of somewhat different nature to those above described was an anomaly described by M. Gay at a meeting of the Botanical Society of France, April 8th, 1859. The plant affected was Leucoium aestivum, and the changes observed were apparently attributable to a simple separation of two leaves that are usually contiguous. "Suppose," says M. Gay in describing this malformation, "the first leaf of the terminal bud separated by a long internode from the other leaves, which remain closely packed; and further, suppose an evident thickening of the upper portion of the lengthened internode, and there will be not only a single bulb, bearing with the leaves of the present year all the remnants of the leaves of the two preceding years, but two bulbs placed one above another, on the same axis, separated by the length of the internode."



The formation of bulbs in the axils of the leaves, as happens occasionally in tulips, is further alluded to under the head of hypertrophy.

Displacements affecting the inflorescence.—These are, for the most part, dependent on hypertrophy, elongation, atrophy, spiral torsion, &c., but there are a few instances of a different nature, which may here be alluded to as not being coincident with any of the phenomena just mentioned. Sometimes these deviations from the ordinary position have the more interest as affecting characters used to distinguish genera; thus one of the distinctions between rye-grass (Lolium) and wheat (Triticum) resides in the relative position of the spikelets and the main stem; in Triticum the spikelets are placed with their backs against the rachis, in Lolium with one edge against it; but in a specimen of rye-grass that has come under my own observation, the arrangement was that of Triticum.

M. Kirschleger relates having found a specimen of Leucanthemum pratense, in which the ligulate female flowers were growing singly in the axils of the upper leaves of the stem.[91] The ordinary capitulum would here seem to have been replaced by a spike or a raceme. A less degree of this change wherein a few flowers may be found, as it were, detached from the ordinary capitulum may often be observed in Compositae, Dipsacaceae, &c. I have also met with specimens of Lamium album in which some of the fascicles or clusters of flowers in place of being placed at the same level on opposite sides of the stem were placed alternately one above another.

Caspary[92] mentions a flower of Aldrovanda vesiculosa, which was elevated on a stalk that was adherent to the stem for a certain distance, and then separated from it. This flower, with the leaf to which it was axillary, evidently belonged to the whorl beneath, where there was a corresponding deficiency. Another flower of the same plant bore on its pedicel a small leaf, which was doubtless the bract raised above its ordinary position.

M. Fournier mentions an instance in Pelargonium grandiflorum, where, owing to the lengthening of the axis, the pedicels, instead of being umbellate, had become racemose; and I owe to the kindness of Dr. Sankey a somewhat similar specimen, but in a less perfect condition. Here there was but a single flower, and that rudimentary, placed at the extremity of the axis. There were several bracts beneath this flower disposed spirally in the 1/3 arrangement, all being empty, excepting the terminal one. In like manner, a head of flowers becomes sometimes converted into an umbel.

Displacement of leaves.—A cohesion of parts will sometimes give rise to an apparent displacement, but the true nature of the malformation can, in general, be readily made out.

Steinheil[93] found a specimen of Salvia Verbenaca, the leaves of which presented very curious examples of displacement arising from cohesion. Two of these leaves placed at the base of a branch were completely fused in their lower thirds, and divided into two distinct lobes at the upper part; each of these lobes seemed to be as large as the limb of an ordinary leaf. Above these was another very broad one, apparently entire, but evidently produced by a complete cohesion of two. This completely fused leaf alternated in position with the imperfectly fused one below it; the alternation is explained by supposing that the opposite leaves of each pair were directed one towards the other, and became fused, and that thus resulted the displacement. The dislocation of the organs took place in one direction for one pair of leaves, and in another direction for the other pair, hence the alternation. Thus, leaves normally opposite and decussate may, by fusion, become alternate. A similar instance occurred to the writer in Lysimachia vulgaris, wherein the changes arising from fusion and suppression of parts, &c., were very considerable; as far as the leaves were concerned they presented the following arrangement in succession from below upwards:—first verticillate, then opposite, then spirally alternate, lastly opposite.[94] The term "diremption" has sometimes been applied to cases where leaves are thus apparently dragged out of position.

In Tradescantia virginica I have met with opposite connate leaves; the altered position, however, being due to the union of two stems.



Twisting of the stem is a frequent cause of the displacement of leaves (see spiral torsion), as also hypertrophy, whether that excess of development take place laterally or lengthwise (see elongation). Atrophy or suppression will also frequently bring about an alteration in the position of leaves; sometimes in such a manner that the place of the suppressed organ is occupied by another one. One of the most curious instances of displacement of leaves arising from suppression is that mentioned by Morren,[95] where, in Gesnera Geroltiana, a large leaf apparently occupied the extremity of the axis, a position which, under ordinary circumstances, no leaf could assume. The explanation given by the Belgian professor is, that the axis in this case, instead of throwing off a pair of leaves, one on each side, had from some cause or another produced only one; this one not only being much larger than ordinary, but brightly coloured, thus assuming some of the characteristics as well as the position of the inflorescence.

Alterations in the usual arrangement of leaves, however, are not always dependent on or coexistent with other teratological changes, but may simply depend on a natural elongation of the internodes, or on fission or multiplication; for instance, in some conifers, such as the Larch, (Abies Larix) or Pinus pinea, there may be found at different stages in the growth of the branches leaves in crowded fascicles or tufts; while, when growth is more rapid, the leaves may be disposed in a spiral or alternate manner.

In the yew (Taxus) the leaves at the ends of the shoots not unfrequently lose their usual distichous arrangement and become arranged in a close spiral manner, the elongation of the shoot being arrested. This appears to be the result of the injury effected by some insect.



So, too, the alteration from verticillate to spiral, or vice versa, may take place without any other notable change.[96] This may frequently be seen in Rhododendrons.

Displacement of the parts of the flower.—This subject is partly touched on in the chapters on solution, adhesion, and in those on hypertrophy, elongation, prolification, &c., so that in this place it is only requisite to offer a few general remarks, and to refer to other sections for further details. Morren, in referring to displacement of the floral organs, mentions an instance in a Fuchsia, wherein the four petals in place of being alternate with the sepals were placed in front of them, owing to the adhesion that had taken place between the petals and the stamens. He speaks of this transposition as metaphery.[97] The same author also gives an account of the displacement of several of the organs of the flower in Cypripedium insigne, the displacement being consequent, apparently, on a spiral torsion proceeding from right to left, and involving the complete or partial suppression of several of the organs of the flower. The dislocation of organs in a spiral direction led Morren to apply the term "speiranthie" to similar deviations from the usual construction. Changes of this kind among Orchidaceae are by no means uncommon; the following may be cited by way of illustration. In a specimen of Oncidium cucullatum furnished me by Mr. Anderson, well known for his success as a cultivator of these plants, there was, associated with a cohesion of one sepal with another, and probably dependent on the same cause, a displacement of the sepals and petals—so that all were dragged out of place. This dislocation may be better appreciated by the accompanying formula than even by the woodcut. Let the usual arrangement be thus represented:

S

P ST P

L

S S

S standing for sepal, P for petal, L for lip, ST for stamen; then the dislocated form may be represented thus:

S

P P

T S

S_S L



In a specimen of Cypripedium also furnished by Mr. Anderson the appearance was as represented in the accompanying figure and diagrams, figs. 44, 45. Referring to the plan of the natural arrangement at fig. 46, it will be seen that an explanation of the peculiar appearance of the flower may be arrived at by supposing a disunion and lateral displacement of the upper segment of the outer perianth together with the complete absence of the lower one. In the second or inner whorl of the perianth the lip is merely a little oblique on one side, but the lateral petals are distorted, displaced, and adherent one to the other and to the column, while the posterior shield-like rudimentary anther is completely wanting.



In a specimen of Lycaste Skinneri similar changes were observed, as shown in the plan, fig. 47. Here the posterior sepal was deficient, the two lateral ones were present, one of them with a long tubular spur, o o; of the two lateral petals, i i, one was twisted out of place, so as partially to occupy the place of the deficient sepal; the lip was represented by two three-lobed segments, l, one above and within the other. The column and ovary of this flower were in their normal condition.

Cohesion of two or more segments of the perianth is frequently associated with displacements of this nature: thus, in a flower of Dendrobium nobile, a diagram of which is given at fig. 48, the uppermost sepal was coherent with one of the lateral ones, and at the same time diminished in size, and, as it were, dragged out of position. All the other organs of the flower are also more or less displaced, forming a minor degree of the change already alluded to, and which Morren termed speiranthy. The changes will be better appreciated by comparing them with fig. 49, a diagram showing the natural arrangement of parts in this species.



Sometimes the displacement seems consequent on hypertrophy of one of the parts of the flower, the disproportionate size of one organ pushing the others out of place. This was the case in a violet, fig. 50, in which one of the sepals s was greatly thickened, and the petals and stamens were displaced in consequence.



It is curious to observe in many of these cases that the transposed organ not only occupies the place of a suppressed or abortive organ, but frequently assumes its colour, and, to some extent, its function. This has been alluded to in the case of the leaf of Gesnera (see p. 88) and in Orchids this replacement seems to be very common; thus, in addition to the cases before mentioned, in a flower of an Odontoglossum, for which I am indebted to Professor Oliver, the two lateral sepals were united together and occupied the position of the labellum, which was absent. A similar occurrence happens occasionally in Lycaste Skinneri, thus recalling the structure of Masdevallia, where the labellum is normally very small. The arrangement in Lycaste may thus be symbolised:

S P st P + S S _

[Transcriber's note: The underscores represent a horizontal curly brace in the original.]

the + indicating the position of the absent labellum.

Cases of this kind are the more interesting from their relation to the fertilization of these flowers by insects; it seems as though, when the labellum, which performs so important an office in attracting and guiding insects, is deficient, its place is supplied by other means.

Displacement of the parts of the flower from elongation of the receptacle is a not infrequent teratological occurrence, resulting sometimes in the conversion of the verticillate into the spiral arrangement. Instances of this are cited under Elongation, Prolification, &c. In this place it is merely necessary to refer to a curious circumstance that is met with in some double flowers, owing to this separation of some parts of the flower and the cohesion or adhesion of others. Thus, in some double flowers of Primula sinensis and in the Pea (Pisum sativum), I have seen a gradual passage of sepals to petals, so that the calyx and corolla formed one continuous sheet, winding spirally around the central axis of the flower, after the fashion of a spiral tube.[98]

Displacement of the carpels arises from one or other of the causes above alluded to, and when suppression takes place in this whorl it generally happens that the place of the suppressed organ is occupied by one of the remaining ones, which thus becomes partially dislocated.

Displacement of the placentas and ovules is a necessary result of many of the changes to which the carpels are subject. The disjunction or dialysis of the carpels, for instance, frequently renders axile placentation marginal. Moreover, it frequently happens, when the carpels become foliaceous and their margins are disconnected, that the ovules, in place of being placed on the suture, or rather on the margins of the altered carpel, are placed on the surface of the expanded carpel. Thus, in some double flowers of Ranunculus Ficaria that came under the writer's notice the carpels were open, i.e. disunited at the margins, and each bore two imperfect ovules upon its inner surface a little way above the base, and midway between the edges of the carpel and the midrib, the ovules being partly enclosed within a little depression or pouch, similar to the pit on the petals. On closer examination the ovules were found to spring from the two lateral divisions of the midrib, the vascular cords of which were prolonged under the form of barred or spiral fusiform tubes into the outer coating of the ovule. In this instance, then, the ovules did not originate from the margins of the leaf, nor from a prolonged axis, but they seemed to spring, in the guise of little buds, from the inner surface of the carpellary leaf.[99]