

OF THE CUTICLE OR EPIDERMIS. 17 



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 ingenious Sir 

 H. 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 Saliv- 

 triandra, rather consists of scales of bark, which 

 having performed their functions and become dead 

 matter, are rejected by the increasing bark beneath 

 them ; and this accords with M. Mirbel's idea of the 

 cuticle. The old layers of bark in the Chesnut, Oak, 

 and many other trees, though not cast off, are of the 

 same nature ; and these under the microscope exhibit 

 the same cellular texture as the real cuticle. 



