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Darwin, Charles, 1809-1882

"The Movements and Habits of Climbing Plants"

--This species is closely allied to the last, and
behaves in the same manner; but perhaps twines rather better round a
vertical stick. On the same plant, one branch twined in one
direction and another in an opposite direction. The internodes in
one case made two circles, each in 2 hrs. 33 m. I was enabled to
observe the spontaneous movements of the petioles better in this than
in the two preceding species: one petiole described three small
vertical ellipses in the course of 11 hrs., whilst another moved in
an irregular spire. Some little time after a stem has twined round
an upright stick, and is securely fastened to it by the clasping
petioles and tendrils, it emits aerial roots from the bases of its
leaves; and these roots curve partly round and adhere to the stick.
This species of Bignonia, therefore, combines four different methods
of climbing generally characteristic of distinct plants, namely,
twining, leaf-climbing, tendril-climbing, and root-climbing.
In the three foregoing species, when the foot-like tendril has caught
an object, it continues to grow and thicken, and ultimately becomes
wonderfully strong, in the same manner as the petioles of leaf-
climbers.


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