2o8 FREAKS OF PLANT LIFE. 



surface of the tip caused it to curve immediately, so 

 that in two minutes it formed an open spire. The 

 movement was generally perceptible within half a 

 minute after being touched. A tendril which curls 

 through being touched, but does not embrace any- 

 thing, straightens itself again, but soon becomes 

 irritated by a second touch. In order to ascertain 

 how often the same tendril may be excited one 

 tendril was selected, and this alternately straightening 

 itself, answered to the stimulus no less than twenty- 

 one times in fifty-four hours. 



Professor Asa Gray has observed an equally rapid 

 response to a touch in the tendrils of a plant of the 

 cucumber family, but instances of such rapidity are 

 rare. In some, the movement takes place after a few 

 minutes, in others it is an hour or two, but in all 

 some exhibition of sensibility has been observed. 

 It is noteworthy that drops of water sprinkled with 

 a syringe, so as to resemble falling rain, in no instance- 

 appeared to have the least stimulating effect. In 

 most cases a touch from another tendril seemed to 

 have no influence, although, in the bryony and the 

 vine other tendrils have been seen embraced. 



The sensibility of tendrils to light may also be 

 illustrated by the trumpet-flower {^Bignonia capreo- 

 lata). In his experiments on these plants, Mr. 

 Darwin observes, " In two instances, a pair of leaves 

 stood so that one of the two tendrils was directed 



