Chap. HI. BIGNONIACE^. 89 



which I have observed ; and it probably could ascend 

 a polished stem incessantly tossed by heavy storms. 

 To show how important vigorous health is for the 

 action of all the parts, I may mention that when I 

 first examined a plant which was growing moderately 

 well, though not vigorously, I concluded that the 

 tendrils acted only like the hooks on a bramble, and 

 that it was the most feeble and inefficient of all 

 climbers ! 



Bignonia Tweedyana. This species is closely allied 

 to the last, and behaves in the same manner; but 

 perhaps twines rather better round a vertical stick. 

 On the same plant, one branch twined in one direction 

 and another in an opposite direction. The internodes 

 in one case made two circles, each in 2 hrs. 33 m. I 

 was enabled to observe the spontaneous movements of 

 the petioles better in this than in the two preceding 

 species: one petiole described three small vertical 

 ellipses in the course of 11 hrs., whilst another 

 moved in an irregular spire. Some little time after 

 a stem has twined round an upright stick, and is 

 securely fastened to it by the clasping petioles and 

 tendrils, it emits aerial roots from the bases of its 

 leaves ; and these roots curve partly round and adhere 

 to the stick. This species of Bignonia, therefore, com- 

 bines four different methods of climbing generally 

 characteristic of distinct plants, namely, twining, leaf- 

 climbing, tendril-climbing, and root-climbing. 



In the three foregoing species, when the foot-like 

 tendril has caught an object, it continues to grow 



