TENDBIL-BEAEERS. 67 



about two hours, and was ready to act again. As soon as the 

 tendrils begin to grow old their extremities become hooked, and 

 they then appear, with their two or three pairs of branches, an 

 admirable grappling instrument ; but this is not really the case, 

 for at this period the tips have generally quite lost their sensitive- 

 ness ; when hooted on to twigs some were not at all affected, and 

 others required from 18 h. to 24h. to clasp the twigs. Ultimately 

 the lateral branches of the tendril, but not the middle or main 

 stem, contract spirally. • 



( 



Laihyrus apliaca. — ^As the tendril here replaces the whole leaf 



replaced in function by the large stipules, it might have been ex- 

 pected that the tendrils would have been highly organized ; this, 

 however, is not so. They are moderately long, thin, and un- 



wi 



young on all sides, but chiefly on the concave side of the extre- 

 mity. They have no spontaneous revolving power, but are at first 

 inclined upwards at an angle of about 45°, then move into a hori- 

 zontal position, and ultimately bend downwards. The young 

 internodes, on the other hand, revolve in ellipses, and carry with 

 them the tendrils : two ellipses were completed, each in nearly 

 5h.; the longer axes of these two, and of some subsequently 

 formed ellipses, were directed at about an angle of 45° from the 

 nne of the axis of the previous ellipse. 



LatJiyriis grandiflorus. — The plants observed were young, and 

 not growing vigorously, yet sufficiently so, I think, for my observa- 

 tions to be trusted. Here we have the rare case of neither inter- 

 nodes nor tendrils having any spontaneous revolving power. The 

 tendrils in vigorous plants are above 4 inches in length, and are 

 often twice divided into three branches ; the tips are curved and 

 are sensitive on the concave^'side ; the lower part of the central stem 

 is hardly at all sensitive. Hence this plant climbs simply by its 

 tendrils being brought, through the growth of the stem, or the more 

 efficient aid of the wind, into contact with surrounding objects, 

 which are then effectually clasped. I may add that the tendrils, or 

 the internodes, or both, of Vicia sativa spontaneously revolve. 



Composite. — Mutisia clematis, — The enormous family of Com- 

 positae is well known to include very few climbing plants. We 

 have seen in the Table in the first Part that MiTcania is a regular 

 twiner, and Mutisia is the only genus, as far as I can learn, which 

 bears tendrils : it is therefore interesting to discover that these 



metamorphosed 



F 2 



