But the main branch
of the tendril, after revolving for a time in a vertical position,
spontaneously bends downwards; and in doing so, raises the spur-like
branch, which itself also curves upwards; so that by these combined
movements it rises above the projecting end of the shoot, and can now
move freely without touching the shoot; and now it first becomes
sensitive.
The tips of both branches, when they come into contact with a stick,
grasp it like any ordinary tendril. But in the course of a few days,
the lower surface swells and becomes developed into a cellular layer,
which adapts itself closely to the wood, and firmly adheres to it.
This layer is analogous to the adhesive discs formed by the
extremities of the tendrils of some species of Bignonia and of
Ampelopsis; but in the Hanburya the layer is developed along the
terminal inner surface, sometimes for a length of 1.75 inches, and
not at the extreme tip. The layer is white, whilst the tendril is
green, and near the tip it is sometimes thicker than the tendril
itself; it generally spreads a little beyond the sides of the
tendril, and is fringed with free elongated cells, which have
enlarged globular or retort-shaped heads.
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