; it swept ellipses with the longer
axes directed at right angles to one another; but the plant,
apparently, cannot twine. The petioles and the tendrils are both in
constant movement. But their movement is slower and much less
regularly elliptical than that of the internodes. They appear to be
much affected by the light, for the whole leaf usually sinks down
during the night and rises during the day, moving, also, during the
day in a crooked course to the west. The tip of the tendril is
highly sensitive on the lower surface; and one which was just touched
with a twig became perceptibly curved in 3 m., and another in 5 m.;
the upper surface is not at all sensitive; the sides are moderately
sensitive, so that two branches which were rubbed on their inner
sides converged and crossed each other. The petiole of the leaf and
the lower parts of the tendril, halfway between the upper leaflet and
the lowest branch, are not sensitive. A tendril after curling from a
touch became straight again in about 6 hrs., and was ready to re-act;
but one that had been so roughly rubbed as to have coiled into a
helix did not become perfectly straight until after 13 hrs. The
tendrils retain their sensibility to an unusually late age; for one
borne by a leaf with five or six fully developed leaves above, was
still active.
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