CuAP. HL 



TENDEIL-BEAKEKS. 



85 



Mold, wlio includes under the name of tendrils various 

 organs having a similar external appearance, classes 

 them according to their homological nature, as being 

 modified leaves, flower-peduncles, &c. This would be 

 an excellent scheme ; but I observe that botanists are 

 by no means unanimous on the homological natuje of 

 certain tendrils. Consequently I will describe tendril- 

 bearing plants by natural families, following Lindley's 

 classification ; and this will in most cases keep those of 

 the same nature together. The species to be described 

 belong to ten families, and will be given in the 

 following order : — Bignoniaeem, Polemoniaceas, Legu- 

 minosse, Compositse, SmUaeese, Fumariaeese, Cucurhitaeese, 

 Vitaeese, Sapindaceae, Passifloraeeae* 



transformed into branches, as with 

 certain Papilionaceous plants. 

 (5.) Plants with their branches 

 forming true tendrils, and used 

 exclusively for climbing — as with 

 Strydmos and Caulotretut. Even 

 the unmodified branches become 

 much thickened when they wind 

 round a support. I may add that 

 Mr. Thwaites sent me from Ceylon 

 a specimen of an Acacia which 

 had climbed up the trunk of a 

 rather large tree, by the aid of 

 tendril-like, curved or convoluted 

 branchlets, arrested in their 

 growth and furnished with sharp 

 recurved hooks. 



* As &r as I can make out, the 

 history of our knowledge of 

 tendrds is as follows: — ^We have 

 seen that Palm and von Mohl 

 observed about the same time the 



singular phenomenon of the spon- 

 taneous revolving movement of 

 twining-planta. Palm (p. 58), I 

 presume, observed likewise the 

 revolving movement of tondrUs; 

 but I do not feel sure of this, for 

 he says very little on the subject. 

 Dutrochet fully described this 

 movement of the tendiil in the 

 common pea. Mohl first discover- 

 ed that temlrils are sensitive to 

 contact ; but from some cause, 

 probably from observing too old 

 tendrils, be was not aware how 

 sensitive they were, and thought 

 that prolonged pressure was neces- 

 sary to excite their movement. 

 Professor Asa Gray, in a paper 

 already quoted, first noticed the 

 extreme sensitiveness and rapidity 

 of the movements of the tendril* 

 of certain Cucurbitaceous plants. 



