The use of the hooks was well shown by giving the
tendrils tubes and slips of glass to catch; for these, though
temporarily seized, were invariably lost, either during the re-
arrangement of the branches or ultimately when spiral contraction
ensued.
The perfect manner in which the branches arranged themselves,
creeping like rootlets over every inequality of the surface and into
any deep crevice, is a pretty sight; for it is perhaps more
effectually performed by this than by any other species. The action
is certainly more conspicuous, as the upper surfaces of the main
stem, as well as of every branch to the extreme hooks, are angular
and green, whilst the lower surfaces are rounded and purple. I was
led to infer, as in former cases, that a less amount of light guided
these movements of the branches of the tendrils. I made many trials
with black and white cards and glass tubes to prove it, but failed
from various causes; yet these trials countenanced the belief. As a
tendril consists of a leaf split into numerous segments, there is
nothing surprising in all the segments turning their upper surfaces
towards the light, as soon as the tendril is caught and the revolving
movement is arrested.
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