98 TENDKIL-BEAKERS. Chap. IIL 



described large regular ellipses. I could detect no 

 spontaneous movement in the petioles of the leaves. 



Whilst the tendrils are revolving more or less 

 regularly, another remarkable movement takes place, 

 namely, a slow inclination from the light towards 

 the darkest side of the house. I repeatedly changed 

 the position of my plants, and some little time after 

 the revolving movement had ceased, the successively 

 formed tendrils always ended by pointing to the 

 darkest side. When I placed a thick post near a 

 tendril, between it and the light, the tendril pointed 

 in that direction. In two instances a pair of leaves 

 stood so that one of the two tendrils was directed 

 towards the light and the other to the darkest side of 

 the house ; the latter did not move, but the opposite 

 one bent itself first upwards and then right over its 

 fellow, so that the two became parallel, one above the 

 other, both pointing to the dark : I then turned the 

 plant half round ; and the tendril which had turned 

 over recovered its original position, and the opposite 

 one which had not before moved, now turned over to 

 the dark side. Lastly, on another plant, three pairs 

 of tendrils were produced at the same time by three 

 shoots, and all happened to be differently directed : I 

 placed the pot in a box open only on one side, and 

 obliquely facing the light ; in two days all six ten- 

 drils pointed with unerring truth to the darkest corner 

 of the box, though to do this each had to bend in a 

 different manner. Six wind-vanes could not have 

 more truly shown the direction of the wind, than did 



