) 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