Ciiap. m. 



TENDKIL-BEARERS. 



85 



Mfthl, who 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 nature 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 : Bignoniacete, Polemoniacex, Legu- 

 minosse, Comjwsitas, Smilaceee, Fumariacess, Cucurhitacese, 

 Vitacess, Sapindaeese, Passifloracete* 



transformed into branches, as with 

 certain Papilionaceous plants. 

 (5.) Plants with their branches 

 forming true tendrils, and used 

 exclusively for climbing as with 

 Strychnos and Caulotretus. 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 far as I can make out, the 

 history of our knowledge of 

 tendrils 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-plants. Palm (p. 58), I 

 presume, observed likewise the 

 revolving movement of tendrils ; 

 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 tendrils are sensitive to 

 contact ; but from some cause, 

 probably from observing too old 

 tendrils, he was not aware how 

 sensitive they were, and thought 

 that prolonged pressure was nc ces- 

 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. 



