COM 1,1 UI NO HE-MARKS. 113 



further inquire how the stems, petioles, tendrils, and flower- 

 pedtmclea of climbing plants first acquired their power of spon- 

 taneously revolving, or, to speak more accurately, of successively 

 bending to all points of the compass, we are again silenced, or 

 at most can only remark, that the power of movement, both spon- 

 taneous and from various stimuli, is far more common with plants, 

 as we shall presently see, than is generally supposed to be the case 

 by those who have not attended to the subject. There is, how- 

 ever, the one remarkable case of the Maurandia semperjlorem, in 

 which the young flower-peduncles spontaneously revolve in very 

 small circles, and bend themselves, when gently rubbed, to the 

 touched side; yet this plant certainly profits in no way by these 

 two feebly developed powers. A rigorous examination of other 

 young plants would probably show some slight spontaneous move- 

 ments in the peduncles and petioles, as well as that sensitiveness 

 to shaking observed by Hofmeieter. We see at least in the Mau- 

 randia a plant; which might, by a little augmentation of qualities 

 which it already possesses, come first to grasp a support by its 

 flower-peduncles (as with Vitis or Cardiospermum) and then, by 

 the abortion of some of its flowers, acquire perfect tendrils. 



There is one interesting point which deserves notice. We have 

 seen that some tendrils have originated from modified leaves, and 

 others from modified flower-peduncles; so that some are foliar and 

 others axial in their homological nature. Hence it might have 

 been expected that they would have presented some difference in 

 function. This is not the case. On the contrary, they present 

 the most perfect identity in their several remarkable character- 

 istics. Tendrils of both kinds spontaneously revolve at about the 

 same rate. Both, when touched, bend quickly to the touched side, 

 and afterwards recover themselves and are able to act again. In 

 both the sensitiveness is either confined to one side or extends all 

 round the tendril. They are either attracted or repelled by the 

 light. The latter case is seen in the foliar tendrils of Bignonia 

 capreolata and in the axial tendrils of the Ampclopsis, both of 

 which move from the light. The tips of the tendrils in these two 

 plants become, after contact, enlarged into disks, which are at 

 first adhesive by the secretion of some cement. Tendrils of both 

 kinds, soon after grasping a support, contract spirally ; they then 

 increase greatly in thickness and strength. When we add to 

 these several points of identity the fact of the petiole of the 

 Solatium jasminoides assuming the most characteristic feature of 

 the axis, namely, a closed ring of woody vessels, we cnw hardly 



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