Page:Darwin - On the movements and habits of climbing plants.djvu/80

 revolved; in the latter plant, Dutrochet saw the movement of the tendril reversed; but whether the internodes as well as the tendrils revolve in these several species I did not observe. In Anguria Warscewiczii, however, the internodes, though thick and stiff, do revolve: in this plant the lower surface of the tendril, some time after clasping a stick, produces a coarsely cellular layer or cushion, fitting the wood, like that formed by the tendril of the Hanburya; but it was not in the least adhesive. In Zanonia Indica, which belongs to a different tribe of the family, both the forked tendrils and the internodes revolved, in periods between 2 h. 8 m. and 3 h. 35 m., moving against the sun.

.—In this family and in the two following, namely, the Sapindaceæ and Passifloraceæ, the tendrils are modified flower-peduncles; so that they are axial in their nature. In this respect they differ from those of all the first described families, but perhaps not from those of the Cucurbitaceæ. The homological nature, however, of a tendril seems to make no difference in its action.

Vitis vinifera.—The tendril is thick and of great size; one from a vine not growing vigorously out of doors, measured 16 inches in length. It consists of a peduncle (A), bearing two branches