DESCRIPTIVE BOTANY. 



PART I. 



Ann. des Sciences for February, 1834, that a lengthened 

 maceration causes it to separate into three parts (Jig. I?.)- 

 The outermost of these, consists of an extremely de- 



licate homogeneous pellicle (a), without any very 

 decided traces of organisation, though occasionally 

 somewhat granulated in its appearance, and also marked 

 by lines, which are merely the spaces left between the 

 impressions made upon it by that portion of the cellular 

 tissue with which it was in contact. It is generally 

 perforated by small oval slits, at the places where 

 the stomata exist. A lamina of flattened vesicles (6), 

 is closely united with this pellicle, and forms the second 

 portion of the epidermis ; the vesicles occupy the 

 spaces included between the linear markings observed 

 upon the surface. Sometimes this part contains more 

 than one lamina of flattened vesicles. The vesicles are 

 in close contact, excepting immediately under the spaces 

 occupied by the slits in the pellicle. The third part 

 alluded to, consists of the stomata (c), which are placed 

 a little further from the pellicle than the lamina of cells 

 last mentioned, and which, as we stated, is in immediate 

 contact with it. 



(30.) Stomata. Each stoma is most generally com- 



