264 



THE SECOND BOOK OF BOTANY. 



find points of attachment. When one has secured a 

 hold, it shortens by curling up so as to draw the main 



FIG. 419. 



stem nearer to its support, then it rapidly becomes 

 thicker and stronger than before. 



Tendrils of the bigonia (Fig. 420) are described 

 by Mr. Darwin as having a revolving movement, and, 

 when they grow through a branch, and come into 

 contact with the twig, the points bend in like claws, 

 and the tendril holds on to the twig exactly like a 

 bird when perched. The same naturalist says that 

 the tendrils of this plant will slowly travel over the 

 surface of a piece of wood, and, when the point, or 

 " toe," of one of them finds a hole or crack, it inserts 



