SENSITIVE PLANTS. 225 



rays of the sun may be concentrated by a lens upon 

 the leaflets without producing any motion ; but when 

 directed upon the leafstalk the response is almost 

 instantaneous. The leaves move rapidly under the 

 influence of an electric shock. 1 



The sensitive plant was the earliest 

 Up-gathered into the bosom of rest ; 

 A sweet child weary of its delight, 

 The feeblest and yet the favourite, 

 Cradled within the embrace of night. 2 



The leaves of the common wood-sorrel not only 

 close in the evening, but if gathered roughly seem to 

 shrink from the touch like the sensitive plant. 

 Another species of wood-sorrel (Oxalis sensitivd), 

 which is a native of Amboyna, is said to be so 

 delicately sensitive that it will not bear the blowing 

 of the wind upon it, without contracting its leaves. 

 Dr. Roxburgh said of it, that ' f it was like a maiden, 

 though common on every wayside, it may be looked 

 at but is not to be touched." 



Thus much is sufficient to explain what are the 

 most manifest phenomena of those which have re- 

 ceived the name of "sensitive plants": in other 

 words, plants which exhibit irritability in a manifest 

 degree. 3 In these instances the leaves possess the 



1 Hogg's "Vegetable Kingdom.'' - Shelley. 



3 Of plants which are reputed to possess this power, the 

 following may be named : — Des?nodium gyrans, Mimosa putkea, 



Q 



