7 m. The
extremity being lightly rubbed on the concave surface, became just
perceptibly curved in 7 m., distinctly in 10 m., and hooked in 20 m.
We have seen that the tendrils in the last three families, namely,
the Vitaceae, Sapindaceae and Passifloraceae, are modified flower-
peduncles. This is likewise the case, according to De Candolle (as
quoted by Mohl), with the tendrils of Brunnichia, one of the
Polygonaceae. In two or three species of Modecca, one of the
Papayaceae, the tendrils, as I hear from Prof. Oliver, occasionally
bear flowers and fruit; so that they are axial in their nature.
The Spiral Contraction of Tendrils.
This movement, which shortens the tendrils and renders them elastic,
commences in half a day, or in a day or two after their extremities
have caught some object. There is no such movement in any leaf-
climber, with the exception of an occasional trace of it in the
petioles of Tropaeolum tricolorum. On the other hand, the tendrils
of all tendril-bearing plants, contract spirally after they have
caught an object with the following exceptions. Firstly, Corydalis
claviculata, but then this plant might be called a leaf-climber.
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