TENDRIL-BEAKERS. 57 



wards the liglit and the other to the darkest side of the house ; the 

 latter did not move, but the opposite one bent itself first upwards 

 and then right over its fellow, so that the two became parallel, 

 one above the other, both pointing to the dark : I then turned the 

 plant half round ; and the tendril which had turned over recovered 

 its original position, and the opposite one, which had not moved 

 before, now turned right over to the dark side. Lastly, on another 

 plant, three pairs of tendrils were produced by three shoots at the 

 same time, and all happened to be differently directed : I placed 

 the pot in a box open only on one side, and obliquely facing the 

 light ; in two days all six tendrils pointed with unerring truth to 

 the darkest corner of the box, though to do this each had to bend 

 in a different manner. Six tattered flags could not have pointed 

 more truly from the wind than did these branched tendrils from 

 the stream of light which entered the box. I left these tendrils 

 undisturbed for above 24 h., and then turned the pot half round; 

 but they had now lost the power of movement, so that they could 

 not any longer avoid the light. 



AVhen a tendril has not succeeded, either through its own re- 

 volving movement or that of the shoot, or by turning towards any 

 object which intercepts the light, in clasping a support, it bends 

 vertically downwards and then towards its own stem, which it 

 seizes together with the supporting stick, if there be one. A little 

 aid is thus given iu keeping the stem secure. If the tendril 

 seizes nothing, it does not contract spirally, but soon withers away 

 and drops off. If it does seize an object, all its branches contract 



spirally. 



I have stated that, after a tendril has come into contact with a 

 stick, in about half an hour it bends round it ; but I repeatedly 

 observed, as with B. speciosa and its allies, that it again loosed 

 the stick : sometimes it seized and loosed the same stick three or 

 four times. Knowing that the tendrils avoided the light, I gave 

 them a glass tube blackened within, and a well-blackened zinc 

 plate : the branches curled round the tube and abruptly bent them- 

 selves round the edges of the zinc plate ; but they soon recoiled, 

 with what I can only call disgust, from these objects, and straight- 

 ened themselves. I then placed close to a pair of tendrils a post 

 with extremely rugged bark ; twice the tendrils touched it for an 

 hour or two. and twice thev withdrew : at last one of the hooked 

 extremities curled round and firmly seized an excessively minute 

 projecting point of bark, and then the other braiiches spread them- 



