We may therefore
conclude that these tendrils are not perfectly adapted to seize
moderately thick sticks or rugged bark. If a thin stick or twig is
placed near a tendril, the terminal branches wind quite round it, and
then seize their own lower branches or the main stem. The stick is
thus firmly, but not neatly, grasped. What the tendrils are really
adapted for, appears to be such objects as the thin culms of certain
grasses, or the long flexible bristles of a brush, or thin rigid
leaves such as those of the Asparagus, all of which they seize in an
admirable manner. This is due to the extremities of the branches
close to the little hooks being extremely sensitive to a touch from
the thinnest object, which they consequently curl round and clasp.
When a small brush, for instance, was placed near a tendril, the tips
of each sub-branch seized one, two, or three of the bristles; and
then the spiral contraction of the several branches brought all these
little parcels close together, so that thirty or forty bristles were
drawn into a single bundle, which afforded an excellent support.
POLEMONIACEAE.--Cobaea scandens.--This is an excellently constructed
climber.
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