430 



SCIENTIFIC AND APPLIED PHARMACOGNOSY 



margin dentate and usually more or less 3-lobed; both surfaces 

 grayish-green, densely velvety pubescent, the midrib and veins of 

 the first order prominent on the lower surface; inodorous; taste 

 mucilaginous. 



INNER STRUCTURE. See Fig. 188. 



Powder. Grayish-green; fragments of non-Kgnified, stellate 

 hairs, usually occurring in clusters of from two to six, having dis- 

 tinctly porous basal portions and attaining a length of 0.600 mm., 

 the walls being about 0.008 mm. in thickness; occasional multi- 

 cellular glandular hairs with short stalks; calcium oxalate in rosette 



m 



FIG. 188. Althaea Folia; A, transverse section through a vein of the leaf; Ep, 

 epidermal cells on the ventral surface; p, palisade cells; g, tracheae; s, lep- 

 tome; O, rosette aggregates of calcium oxalate; Ed, epidermal cells of the 

 dorsal or lower surface. B, longitudinal section through stellate hair on 

 dorsal surface, and showing the calcium oxalate crystals in the cells beneath. 

 C, transverse section through one of the principal veins; c, collenchyma; m, 

 mesophyll; G, tracheae; S, leptome. After Meyer. 



aggregates from 0.015 to 0.025 mm. in diameter; fragments of epi- 

 dermal tissue with stomata, the latter being about 0.025 mm. in 

 length; mucilage cells distinguished by their highly refracting con- 

 tents; usually a few pollen grains, spheroidal, covered with spines, 

 and about 0.100 mm. in diameter. (Newcomb.) 



Constituents. The chemical constituents of the leaves have 

 not been carefully investigated, and in addition to the usual constit- 

 uents found in leaves, they contain an appreciable quantity of 



