STRUCTURE.] 



STOMATES. 



137 



2. OfStomates. 



Fig. 14. 



In most plants the cuticle has certain openings of a very 

 peculiar character, which appear connected with respira- 

 tion, and which are called Stomates, Stomata, or Stomatia. 

 (Plate III. passim.) 



STOMATES are passages through the cuticle, having the 

 appearance of an oval or circular space, in the centre of 

 which is a slit that opens or closes according to circum- 

 stances, and lies ahove a cavity in the subjacent tissue. 



There is, perhaps, nothing in the structure of plants upon 

 which more different opinions have been formed than these 

 stomates. Malpighi and Grew, the latter of whom seems 

 first to have figured them (t. 48., fig. 4.), call them openings 

 or apertures, but had no exact idea of their structure. Mir- 

 bel also for a long time, considered them pores, and figured 

 them as such ; admitting, however, that he suspected the 

 openings to be an optical deception. De Candolle enter- 

 tained no doubt of their being passages through the epidermis. 

 He says their edge has the appearance of a kind of oval 

 sphincter, capable of opening and shutting. The membrane 

 that surrounds this sphincter is always continuous with that 

 which constitutes the network of the epidermis : under the 

 latter, and in the interval between the pore and the edge of 

 the sphincter, are often found molecules of adhesive green 



