It is a rare circumstance thus to detect any
superfluity or imperfection in the action of tendrils--organs which
are so excellently adapted for the functions which they have to
perform; but we see that they are not always perfect, and it would be
rash to assume that any existing tendril has reached the utmost limit
of perfection.
Some tendrils have their revolving motion accelerated or retarded, in
moving to or from the light; others, as with the Pea, seem
indifferent to its action; others move steadily from the light to the
dark, and this aids them in an important manner in finding a support.
For instance, the tendrils of Bignonia capreolata bend from the light
to the dark as truly as a wind-vane from the wind. In the
Eccremocarpus the extremities alone twist and turn about so as to
bring their finer branches and hooks into close contact with any dark
surface, or into crevices and holes.
A short time after a tendril has caught a support, it contracts with
some rare exceptions into a spire; but the manner of contraction and
the several important advantages thus gained have been discussed so
lately, that nothing need here be repeated on the subject.
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