LECT. XI.] ANATOMY OF LEAVES. 603 



slice of the leaf of Dianthus under the micro- 

 scope, to examine this layer in its thickness, we 

 can readily distinguish it (b. 4 1 .), by the form of 

 its cells (c.) from the parenchyma (d. d.) upon 

 which it rests; and, also, from the epidermis 

 (a.) which covers it; for, in this leaf, the cells of 

 the parenchyma assume an oblong form im- 

 mediately under the cutis, whereas the cells of 

 the cutis are irregular spheroids, and the simple 

 layer of epidermis is remarkably distinct. 



Whether these cuticular cells have any direct 

 communication with the oblong cells beneath 

 them, I have not been able to determine; but in 

 separating the cutis, by tearing, some of the ob- 

 long cells always adhere to it; and, when viewed 

 through it, by transmitted light, appear like a 

 smaller cuticular network (d. d. 40.), filling up 

 the larger meshes. These might be mistaken for 

 the cuticular cells; but the transparency of the 

 cutis prevents its cells (e. 4 1 .) from being visible 

 in a superficial view of the organ. In this trans- 

 verse section of the leaf of Dianthus (41.) the dis- 

 tinct nature of the epidermis (a.) is perfectly evi- 

 dent, both as a covering to the true cutis (b.) and 

 as lining the slits (e.), one of which is here di- 

 vided lengthways. 



taken from the under disk of the leaf of Hoya carnosa; and 

 figure 4-, a portion from the upper disk of the same leaf. Both 

 are magnified about 300 times. 



