8 m. and 3 hrs. 35 m., moving against the
sun.
VITACEAE.--In this family and in the two following, namely, the
Sapindaceae and Passifloraceae, the tendrils are modified flower-
peduncles; and are therefore axial in their nature. In this respect
they differ from all those previously described, with the exception,
perhaps, of the Cucurbitaceae. The homological nature, however, of a
tendril seems to make no difference in its action.
Vitis vinifera.--The tendril is thick and of great length; one from a
vine growing out of doors and not vigorously, was 16 inches long. It
consists of a peduncle (A), bearing two branches which diverge
equally from it. One of the branches (B) has a scale at its base; it
is always, as far as I have seen, longer than the other and often
bifurcates. The branches when rubbed become curved, and subsequently
straighten themselves. After a tendril has clasped any object with
its extremity, it contracts spirally; but this does not occur (Palm,
p. 56) when no object has been seized. The tendrils move
spontaneously from side to side; and on a very hot day, one made two
elliptical revolutions, at an average rate of 2 hrs. 15 m.
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