of the Tendrils of Plants. 317 
these creeping dependent plants, but that their stems also, are 
made to recede from light, and to press against the opake 
bodies, which nature intended to support and protect them. 
M. Decandole, I believe, first observed that the succulent 
shoots of trees and herbaceous plants, which do not depend 
upon others for support, are bent towards the point from 
which they receive light, by the contraction of the cellular 
substance of their bark, upon that side, and I believe his opi- 
nion to be perfectly well founded. The operation of light 
upon the tendrils and stems of the ampelopsis and ivy appears 
to produce diametrically opposite effects, and to occasion an 
extension of the cellular bark, wherever that is exposed to its 
influence ; and this circumstance affords, I think, a satisfactory 
explanation why these plants appear to seek and approach 
contiguous opake objects, just as they would do, if they were 
conscious of their own feebleness, and of power in the objects, 
to which they approach, to afford them support and protec- 
tion. 
The tendril of the vine, as I have already stated, is inter- 
nally similar to that of the ampelopsis, though its external 
form, and mode of attaching itself, by twining round any 
slender body, are very different. Some young plants of this 
species, which had been raised in pots in the preceding year, 
and had been headed down to a single bud, were placed in a 
forcing-house, with the plants I have already mentioned ; and 
the shoots from these were bound to slender bars of wood, 
and trained perpendicularly upwards. Their tendrils, like 
those of the ampelopsis, when first emitted, pointed upwards ; 
but they gradually formed an increasing angle with the stems, 
and ultimately pointed perpendicularly downwards ; no object 
mdcccxii. T t 
