11-1 TENDEIL-BEAEEES. Chap. III. 



secured the intern odes ; when this was done, I could 

 never detect any moTement in the petiole, except to 

 and from the b'ght. 



The tendrils, on the other hand, when the intemodes 

 and petioles are secured, describe irregular spires or 

 regular ellipses, exactly like those made by the inter- 

 nodes. A young tendril, only 1| inch in length, 

 rcTolved. Dutrochet has shown that when a plant is 

 placed in a room, so that the light enters laterally, the 

 interhodes travel much quicker to the light than from 

 it : on the other hand, he asserts that the tendril itself 

 moves from the light towards the dark side of the 

 room. With due deference to this great observer, I 

 think he was mistaken, owing to his not having 

 secured the intemodes. I took a young plant with 

 highly sensitive tendrils, and tied the petiole so that 

 the tendril alone could move ; it completed a perfect 

 ellipse in 1 hr. 30 m. ; I then turned the plant partly 

 round, but this made no change in the direction 

 of the succeeding ellipse. The next day I watched a 

 plant similarly secured until the tendril (which was 

 highly sensitive) made an ellipse in a line exactly to 

 and from the light ; the movement was so great that 

 the tendril at the two ends of its eUiptical course 

 bent itself a little beneath the horizon, thus travelling 

 more than 180 degrees; but the curvature was fully 

 as great towards the light as towards the dark side 

 of the room. I believe Dutrochet was misled by not 

 having secured the intemodes, and by having observed 

 a plant of which the intemodes and tendrils no longer 



