The extremity
of the stem is more or less bent downwards, but it never reverses its
curvature, as so generally occurs with twining plants.
Various authors (Palm, p. 55; Mohl, p. 45; Lindley, &c.) believe that
the tendrils of the vine are modified flower-peduncles. I here give
a drawing (fig. 10) of the ordinary state of a young flower-stalk:
it consists of the "common peduncle" (A); of the "flower-tendril"
(B), which is represented as having caught a twig; and of the "sub-
peduncle" (C) bearing the flower-buds. The whole moves
spontaneously, like a true tendril, but in a less degree; the
movement, however, is greater when the sub-peduncle (C) does not bear
many flower-buds. The common peduncle (A) has not the power of
clasping a support, nor has the corresponding part of a true tendril.
The flower-tendril (B) is always longer than the sub-peduncle (C) and
has a scale at its base; it sometimes bifurcates, and therefore
corresponds in every detail with the longer scale-bearing branch (B,
fig. 9) of the true tendril. It is, however, inclined backwards
from the sub-peduncle (C), or stands at right angles with it, and is
thus adapted to aid in carrying the future bunch of grapes.
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