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Darwin, Charles, 1809-1882

"The Movements and Habits of Climbing Plants"

The movement is,
also, now slow, two ellipses being completed conjointly in 24 hrs. 18
m. A mature tendril made an ellipse in 6 hrs.; so that it moved much
more slowly than the internodes. The ellipses which were swept, both
in a vertical and horizontal plane, were of large size. The petioles
are not in the least sensitive, but revolve like the tendrils. We
thus see that the young internodes, the petioles, and the tendrils
all continue revolving together, but at different rates. The
movements of the tendrils which rise opposite one another are quite
independent. Hence, when the whole shoot is allowed freely to
revolve, nothing can be more intricate than the course followed by
the extremity of each tendril. A wide space is thus irregularly
searched for some object to be grasped.
One other curious point remains to be mentioned. In the course of a
few days after the toes have closely clasped a stick, their blunt
extremities become developed, though not invariably, into irregular
disc-like balls which have the power of adhering firmly to the wood.
As similar cellular outgrowths will be fully described under B.
capreolata, I will here say nothing more about them.


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