302 COMPOSITE ORGANS. CHAP. II. 



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SECTION I. 



Of the Structure of the Vegetable Epidermis. 



THE Epidermis of the Vegetable, which, from its 

 resemblance to that of the animal, has been de- 

 signated by the same name, is the external enve- 

 lope or integument of the plant, extending over 

 the whole surface, and covering the root, stem, 

 branches, leaves, flower, and fruit, with their ap- 

 pendages ; the summit of the pistil only excepted. 

 But although it is extended over the whole surface 

 of the plant, it is not of equal consistence through- 

 out. In the root and trunk it is a tough and 

 leathery membrane, or it is a crust of considerable 

 thickness, forming a notable portion of the bark, 

 and assuming some peculiar shade of colour which 

 it seems to acquire from age ; while in the leaves, 

 flowers, and tender shoots it is a fine, colourless, 

 and transparent film, not thicker than a cobweb. 

 But its want of colour is discoverable only when 

 detached ; for, when adherent, it is always tinged 

 with some peculiar shade, which it borrows from 

 the parts immediately beneath it. Hence the green 

 colour so prevalent in the leaf and tender shoot, 

 which the epidermis merely transmits, and the 

 beautiful variety of lines displayed in flowers and 

 fruits. And yet the colour is sometimes inherent 

 even in the epidermis itself, as may be seen by 





