TENDRIL-BEAREKS. G3 



dril thus standing vertically up sweeps a circle right above the stem, 

 and is well adapted to catch some object above, and to favour the 

 ascent of the plant. The whole leaf, with its tendril, after a short 

 time, bends downwards to one side, allowing the next succeeding 

 leaf to become vertical, and ultimately it assumes a horizontal 

 position ; but, before this has occurred, the tendril, supposing it 

 to have caught nothing, has lost its powers of movement and has 

 spirally contracted Into an entangled mass. In accordance with 

 the rapidity of all the movements, their duration is short : in a 

 plant growing vigorously from being placed in a hot-house, a 

 tendril only revolved for about 36 hours, counting from the period 

 when it became sensitive; but during this period it probably 

 made at least 27 revolutions. 



When the branches of a revolving tendril strike against a stick, 



they quickly bend round and clasp it ; but the little hooks play 

 an important part, especially if only the extremity of the tendril 

 be caught, in preventing its being dragged by the rapid revolving 

 movement away too quickly for its irritability to act. As soon 

 as a tendril has bent round a smooth stick or a thick rugged post, 

 or has come into contact with planed wood (for it can at least 

 temporarily adhere even to so smooth a surface as this), the same 

 peculiar movements begin in the branchlets as have been described 

 in those of the Bignonia capreolafa and the Eccremocarpus^ namely, 

 the branchlets lift themselves up and down ; those, however, which 

 have their hooks already directed downwards i^emain in this posi- 

 tion and secure the tendril, whilst the others twist about till they 

 arrange themselves in conformity with every irregularity of the 

 surface, and bring their hooks, originally facing in various direc- 

 tions, into contact with the wood. The use of the hooks was 

 shown by giving the tendrils tubes and slips of glass to catch ; for 

 these, though temporarily seized, were afterwards invariably lost, 

 either during the arrangement of the branches or when the spiral 

 contraction ensued. 



The perfect manner in which the branches arrange themselves, 

 creeping like rootlets over all the inequalities and into any deep 

 crevice, is quite a pretty sight ; for it is perhaps more effec- 

 tually done than by the tendrils of the former species, and is cer- 

 tainly more conspicuous, as the upper surfaces of the main stem 

 and of every branch to the extreme hooks are angular and coloured 

 green, whilst the lower surfaces are rounded and purple. I was 

 led to Infer, as in the former cases, that light guided these con- 

 forming movements of the branches of the tendrils. I made 



