136 TENDKIL-BEAKEES. Chap. IV. 



After a tendril has once firmly coiled itself round 

 a stick, it is difficult to imagine of what use the ad- 

 hesive cellular layer can be. Owing to the spiral 

 contraction which soon ensues, the tendrils were never 

 able to remain, excepting in one instance, in contact 

 with a thick post or a nearly flat surface ; if they had 

 quickly become attached by means of the adhesive 

 layer, this would evidently have been of service to the 

 plant. 



The tendrils of Bryonia dioica, Cucurlita ovifera, 

 and Oucumis satioa are sensitive and revolve. Whether 

 the intemodes likewise revolve I did not observe. In 

 Anguria Warseewiezii, the intemodes, though thick 

 and stiff, revolve : in this plant the lower surface of 

 the tendril, some time after clasping a stick, produces 

 a coarsely cellular layer or cushion, which adapts itself 

 closely to the wood, like that formed by the tendril of 

 the Hanhurya ; but it is not in the least adhesive. In 

 Zanonia Indica, which belongs to a different tribe of 

 the family, the forked tendrils and the intemodes re- 

 volve in periods between 2 hrs. 8 m. and 3 hrs. 35 m., 

 moving against the sun. 



YiTACE^. — In this family and in the two following, 

 namely, the Sapindaceae and Passifloraceae, the tendrils 

 are modified flower-peduncles ; and are therefore axial 

 in their nature. In this respect they differ from all 

 those previously described, with the exception, per- 

 haps, of the Cucurbitaceae. The homological nature, 

 however, of a tendril seems to make no difference 

 in its action. 



