Spilanthes oleracea.

Dahlia.

*Leontodon Taraxac.u.m!

Senecio Doria.

Cichorium Intybus.

Lactuca sativa.

Anthemis retusa.

*Campanula medium!

persicifolia.

Azalea indica!

Vinca minor.

Atropa Belladonna.

*Solanum Lycopersic.u.m!

*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 Clemat.i.tis.

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.

Colchic.u.m autumnale.

Narcissus incomparabilis!

Tazetta.

biflorus.

chrysanthus.

*Ophrys aranifera!

Calanthe vest.i.ta!

Oncidium bicolor.

ornithorhync.u.m.

&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. a.s.soc.

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_, _Taraxac.u.m_, _Saxifraga_, _Silene_, _Hyacinthus_, _&c._ Miquel, 'Linnaea,' xi, p. 423, _Colchic.u.m_. 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 ma.s.s of flowers const.i.tuting 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 a.s.sume 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 circ.u.mstances 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 part.i.tion, 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 cl.u.s.ters were terminated by a compound grape. Seringe has remarked sometimes two, sometimes three, fruits of _Ranunculus tripart.i.tus_ 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 cuc.u.mbers 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.

[Ill.u.s.tration: FIG. 19.--Adhesion of two apples.]

[Ill.u.s.tration: FIG. 20.--Section of united apples.]

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

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

M. Roeper has observed two apples grafted together, one of which had its stalk broken, and seemed evidently borne and nourished by the other apple;[51] and a similar occurrence happens not infrequently in the cuc.u.mber. 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 a.n.a.logous 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 caespit.i.tium_, _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,'