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]

[Illustration: FIG. 21.--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 roots were thus
t