OF THE CUTICLE OR EPIDERMIS. 21 



The leaf of the White Willow is clothed 

 with a fine silky or satiny cuticle. 



The cuticle of the Betony, and of many 

 other plants, is extended into rigid hairs or 

 bristles, which in the Nettle are perforated 

 and contain a venomous fluid. 



On the fruit of the Plum, and on many 

 leaves, we find a blueish dry powder covering 

 the cuticle, which is a resinous exudation, and 

 it is difiicult to wet the surface of these plants. 

 Rain trickles over them in large drops. 



In the Cork tree, the Common Maple, and 

 even the Dutch Elm, the cuticle is covered 

 with a fungous substance most extraordinary 

 in its nature, though familiar to us as cork. 



In grasses and some other plants the inge- 

 nious Mr. Davy has found a flinty substance 

 in the cuticle. 



What seems to be the cuticle on the trunk 

 of the Plane, the Fir, and a kind of Willow 

 called Salix triandra, rather consists of 

 scales of bark, which having performed their 

 functions and become dead matter, are re- 

 jected by the increasing bark beneath them ; 

 and this accords with M. Mirbel's idea of 



