FOOTNOTES:

Fig.12.â€”Crocus.Adhesion of petaloid stamens to perianth.

Adhesion of stamens to pistils.â€”The stamens also may be united to the pistils, as in gynandrous plants. Moquin speaks of such a case in aScabious; M. Clos inVerbascum 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.â€”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 lowerlip of the corolla ofSalvia 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.

Fig.13.â€”Cheiranthus cheiri. Adhesion of petal to stamen and open carpel.

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

Adhesion of fruit to branch.â€”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.â€”Adhesion of two or more flowers takes place in various ways; sometimes merely the stalksare 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 inUmbelliferÃ¦. 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 VÃ©gÃ©tale,' Plates 14 and 15, are figured cases of fusion of the flower stems of the Hyacinth and of aCentaurea. 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 theCampanulafigured in the cut (fig. 14).

Fig.14.â€”Synanthic flowers ofCampanula medium.

Synanthy may take place without much derangement of the structure of either flower, or the union may be attended with abortion or suppression of some of theparts 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 inLonicera, in the common tomato, inPomax,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 inNarcissus 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 inAristolochia 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 ofMatthiola 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 ofNarcissus incomparabilisI 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.

Fig.15.â€”Union of three flowers ofCalanthe vestita.

Fig.16.â€”Shows the abortion of the central spur in synanthic flowers ofCalanthe vestita.

As an illustration of a more complicated nature reference may be made to three flowers ofAconitum Napellus, figured by A. de Chamisso, 'LinnÃ¦a,' 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 ofCalanthe vestitasent me by Dr. Moore, of Glasnevin, in which all the parts usually existing inthree 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.

Fig.17.â€”Synanthy and other changes in a Foxglove.

One of the most singular recorded instances of changes connected with fusion of the flowers is thatcited by Reinsch,[43]where two female flowers ofSalix cinereawere 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 aCalceolariaa 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.

Fig.18.â€”Synanthic flowers of Calceolaria in which, with two upper lips, there was but a single lower one.

Sometimes the upper lips of two flowers are fused into one, the two lower remaining distinct. In other cases, the upper lip disappears altogether, while there are two lower lips placed opposite one another;, of the stamens, sometimesthe 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 ofPolygonatum 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 ofOphrys 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 inCentranthus 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 ofBetonica alopecuroswas 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 otheras 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 synanthicCalceolarias, 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 questionis 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.!Å’nothera sp.Saxifraga sp.Podalyria myrtillifolia.Prunus Armeniaca.spinosa.Pyrus Malus.Persica vulgaris.CratÃ¦gus 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.!Ã†schynanthus 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:â€”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, 'MÃ©m. 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, 'LinnÃ¦a,' xi, p. 423,Colchicum. Michel, 'TraitÃ© du Citronnier,' tab. 6,Citrus.

Syncarpy.â€”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 manyCaprifoliaceÃ¦,RubiaceÃ¦, &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 whatis, 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 Shakespeareâ€”

"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 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 ofRanunculus tripartitussoldered 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 NÃ©fle 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. KÅ“nig 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.

Fig.19.â€”Adhesion of two apples.

Fig.20.â€”Section of united apples.

In many of these cases, where the fruits are united by their bases, the summits become separated one from the other, so as to resemble the letter V. Such divergenceis 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. RÅ“per 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 someLeguminosÃ¦, 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 inGleditschia triacanthosandCÃ¦salpinia digynathis 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:â€”Buxbaumia indusiata,Leskea sericea,Hypnum lutescens,Anomodon alternatus,Clinacium dendroides,Bryum cÃ¦spititium,Brachythecium plumosum,Mnium serratum,Splachnum vasculosum. It has also been observed inTrichostomum rigidulumandHypnum triquetrum.

In addition to the authorities already mentioned, the reader may consult Moquin-Tandon, 'El. Ter. Veg.,' p. 270. Turpin. 'MÃ©m. 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.â€”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.â€”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]

Fig.21.â€”Adhesion of two distinct stems of oak, or possibly cohesion of branches of the same tree. 'Gard. Chron.,' 1846, p. 252.

A similar anastomosis may take place in the roots. Lindley cites a case wherein two carrots, of the white Belgian and the red Surrey varieties respectively, had grown so close to each other that each twisted half round the other, so that they ultimately became soldered together; the most singular thing with reference to this union was, that the red carrot(fig. 23,b), with its small overgrown part above the junction, took the colour and large dimensions of the white Belgian (d), which, in like manner, with its larger head above the joining (a), took the colour and small dimensions of the red one at and below the union (e d). The respective qualities of the two rootswere 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).

Fig.22.â€”Adhesion of the branches of two elms. 'Gard. Chron.,' 1849, p. 421.

The explanation of the fact that the stumps of felled fir trees occasionally continue to grow, and to deposit fresh zones of wood over the stump, depends on similar facts. InAbies 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.

Fig.23.â€”Adhesion of two roots of carrot. 'Gard. Chron.,' 1851, p. 67.

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

The garden operations of budding, grafting and inarching have already been alluded to as furnishing illustrations of adhesion, but it may be well to refer briefly to certain other interesting examples of adhesioninduced 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]

Fig.24.â€”Section through two adherent mushrooms, the upper one inverted.

Mr. Darwin, in his work on the 'Variation of Animals and Plants,' vol. i, p. 395, alludes to the two following remarkable cases of fusion:â€”"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, othersblue, while some produced tubers partly white and partly blue.

Adhesion of the axes of plants belonging to different species is amore 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 ofSophorapassed through the fork, made by two diverging branches of an elder (Sambucus), growing in the Jardin des Plantes of Toulouse. The branch of theSophoracontracted a firm adhesion to the elder, and what is remarkable is that, although the latter has muchsofter 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.â€”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), theCycadeÃ¦,ConiferÃ¦, &c., where there is frequently more than one embryo in the seed. Alphonse De Candolle has described and figured an instance of the kind inEuphorbia helioscopia, wherein two embryo plants were completely grafted together throughout the whole lengthof their axes, leaving merely the four cotyledons separate. A similar adnation has been observed by the same botanist inLepidium sativumandSinapis ramosa, as well as in other plants.[64]I have met with corresponding instances inAntirrhinum majusand inCratÃ¦gus 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 aFuchsia, 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 ofFuchsia coccinea(quereF. magellanica?) by the pollen ofF. 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]'MÃ©m. Acad. Toulouse,' 5th Series, vol. iii.[39]LinnÃ¦a, 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 ofCentaurea Jaceawere united together.[47]'Bull. Bot.' tab. iii, figs. 4â€“6.[48]'MÃ©m. 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. VÃ©gÃ©t.,' tom. ii, p. 781.[52]Sched. de monstr. plant. 'Act. Helv.,' tab. i, fig. 8.[53]'MÃ©m. greffe,' loc. cit., tab. xxiv, p. 334.[54]'Bull. Soc. Bot. Franc.,' 8, pp. 73 and 351, tab. ii; and RÃ¶se. 'Bot. Zeit.,' x, p. 410.[55]NymphÃ¦a lutea,Ã†sculus 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 VÃ©gÃ©t.,' t. iv, p. 426. The same author also cites Romer as having found two plants ofRanunculus, 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 VÃ©gÃ©t.,' t. ii, p. 72, tab. liv, fig. 1.[65]'Bull. Acad. Belg.,' t. xx, part i, 1852, p. 43.

[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.

[39]LinnÃ¦a, 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 ofCentaurea Jaceawere united together.

[47]'Bull. Bot.' tab. iii, figs. 4â€“6.

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

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

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

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

[55]NymphÃ¦a lutea,Ã†sculus 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 VÃ©gÃ©t.,' t. iv, p. 426. The same author also cites Romer as having found two plants ofRanunculus, 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.

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

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 actualbonÃ¢ fideseparation 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 (Î¼Î¿Î½Ï‰ÏƒÎ¹Ï‚) for all these cases of abnormal isolation, subdividing the group into two, as followsâ€”1, Adesmy (Î±-Î´ÎµÏƒÎ¼Î¿Ï‚), including those cases where the separation is congenital; and 2, Dialysis (Î´Î¹Î±Î»Ï…Ï‰), 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.

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