FABRIC OF PLANTS. 



breathing pores of insects, as may be seen in the fol- 

 lowing comparative figures. 



Pores : a, a, pores of plants open; b, b t the same shut; c, breath- 

 ing pore or spiracle of an insect open ; d, the same shut. 



The Coloured Rind. 



Immediately under the outer rind, which, as I have 

 said, is often transparent and colourless, there is a 

 layer 1 composed of small cells, among whose interstices 

 coloured globules are dispersed. In young stems and 

 leaves it as commonly of a green colour. In young 

 branches it is the green bark immediately beneath the 

 rind. 



This, according to Dutrochet and other authorities, 

 performs very important functions, as we shall after- 

 wards see. 



THE INNER BARK. 



THE bark 2 _, exclusive of the rind, consists of two 

 layers, which cannot however be always distinguished. 



(1) In Latin, Integvmentum herbaceum. 

 (2) In Latin, Cortex. 



