100 



Y3nus's fly-trap (Dionoea miiscipula), its sides spas-» 

 modically approach each other, and crush to death: ti 

 the intruder. If the inner side, near the base, of any 

 one of the anthers of the barberry {Bei-heris vulgaris) 

 be gently touched, as with a bristle or feather, it; i 

 instantly springs forward and strikes against the 

 stigma. But the strongest indication, says Mr. Keith, 

 of the existence of a species of sensitive principle in 

 a plant, is, perhaps, that which is exhibited by the 

 Hedysarum gyrans. It is a native of India, growing 

 on the banks of the Ganges. Its leaves are ternate, 

 the middle leaflet being larger than the lateral ones. 

 All of them are in constant vibratory motion ; some- 

 times equably, at other times abruptly, but without 

 any unison in the movements. If their motion be 

 prevented, by grasping them in the hand, they renew 

 it more vigorously when the confinement is removed, 

 but by degrees subside to their natural rapidity of 

 motion. This motion does not depend upon the ap- 

 plication of any external stimulus, for it continues 

 throughout the night as well as the day. It is most 

 active during a warm day, the leaves then having an 

 additional tremulous motion. (KeitJis Sy stein of 

 Physiological Botany, ii. 464.) 



Instinct seems to be a characteristic of plants, from 

 the following phenomena. Some of them close their 

 flowers invariably when rain is approaching. Others 

 have an unalterable direction assumed by them when 



