MICROSCOPICAL EXAMINATION OF POWDERED VEGETABLE DRUGS 95 



5 4 Color and external markings. 

 7 3 Stomata. Often wanting. For characteristics see lower 



epidermis. 

 2 2 Lower epidermis. Make careful comparisons with upper 



epidermis. 



I 3 General outline of cells. 



2 3 Measurements. Transverse diameter usually somewhat 

 more than that of upper epidermis. Vertical 

 diameter usually less. 

 3 3 Cuticle. Usually thinner than upper. Characteristic 



thickenings. 

 4 3 Outer wall. Sometimes with diagnostic modifications. 



(Coca leaves.) 

 5 3 Vertical walls. More generally wavy in outline than those 



of upper epidermis. 

 6 3 Hair cells. Usually much more numerous than upper 



epidermis. (See upper epidermis.) 



7 3 Stomata. 1 Nearly always present. Vertical or surface 

 view to show the striking structural character- 

 istics. 

 I 4 Number. Variable, but not diagnostic, excepting when 



comparing upper and lower epidermis. 

 2 4 Size (of guard cells). Somewhat variable, but rarely 



diagnostic. 

 3 4 Guard cells. Difficult to see in leaves with thick cuticle, 



as in eucalyptus. 

 I 5 Form. Constant in vertical view; variable in profile 



view. Not diagnostic. 



2 5 Contents. Chlorophyll and occasionally coloring matter. 

 4 4 Nebenzellen. 2 Sometimes quite characteristic. Com- 

 pare carefully with normal epidermal cells. 

 I 5 Number to each stoma. From two to five or six. 



Number sometimes diagnestic. 



2 5 Variations in size. Sometimes diagnostic (senna). 

 3 5 Markings (cuticular). Sometimes quite different from 



those of normal epidermal cells. 



4 6 Outer wall of cells. Sometimes quite different in form 

 from normal cells (coca). 



1 When stomata are wanting in an epidermal fragment, it indicates that said 

 fragment belongs to the lower epidermis. When stomata are present on both sides 

 it will be found that they are quite generally more numerous in the lower epidermis. 



2 The English equivalent for this German term is neighboring cells. 



