TENDRILS OF PLANTS. 39 



changed, and care was taken to adjust its surface to the varying 

 position of the sun, so that the light reflected might continue and receded 

 to strike the tendrils ; which then receded from the glass, and i ngone# 

 appeared to be strongly repulsed by it. 



The tendrils of the ampelopsis very closely resemble those The claws of 

 of the vine, in their internal organization, and in originating gj^jj'ariv a"* 

 from the alburnous substance of the plant ; and in being, under fected.bot at 

 certain circumstances, convertible into fruit stalks. The claws, ledS dl$tances - 

 or claspers of the ivy, to experiments upon which I shall now 

 proceed, appear to be cortical protrusions only ; but to be 

 capable, I have reason to believe, of becoming perfect roots, 

 under favourable circumstances. Experiments, in every re- 

 spect very nearly similar to the preceding, were made upon 

 this plant ; but I found it necessary to place the different sub- 

 stances, to which I proposed that the claws should attempt to 

 attach themselves, almost in contact with the stems of the 

 plants. I observed, that the claws of this plant evaded the 

 light, just as the tendrils of the ampelopsis had done ; and 

 that they sprang only from such parts of the stems as were 

 fully or partially shaded. 



A seedling plant of the peach tree, and one of the ampe- The stems of 

 lopsis and ivy, were placed nearly in the centie of the house, l "^ v cr . ee l >er » 

 and under similar circumstances j except that supports, formed inclined to-' 

 of very slender bars of wood, about four inches high, were wards a tree * 

 applied to the ampelopsis and ivy. The .peach tree continued 

 to grow nearly perpendicularly, with a slight inclination to- 

 wards the front and south side of the house, whilst the stems 

 of the ampelopsis and ivy, as soon as they exceeded the height 

 of their supports, inclined many points from the perpendicular 

 line, in the opposite direction. 



It appears, therefore, that not only the tendrils and claws of Not only the 



these creeping dependent plants but that their stems also, are tf ndr, k»but 

 j / i- I 1 • . . - the stems of 



made to recede from light, and to press against the opaque plants incline 



bodies, which nature intended to support and protect them. to their »"P- 

 M. Decandole, I believe, first observed, that the succulent This effect is 

 shoots of trees and herbaceous plants, which do not depend opposite to the 

 upon others for support, are bent towards the point from succulent" 

 which they receive light, by the contraction of the cellular plant?, 

 substance of their bark, upon that side, and I believe his opi- 

 nion to be perfectly well founded. The operation of light 



upon 



