72 



HISTOLOGY OF MEDICINAL PLANTS 



Cowage hairs (Plate 7, Fig. 3) are lance-shaped, and they 

 terminate in a sharp point. The outer wall contains numerous 

 recurved teeth-like projections. The cell cavity is filled with 

 a reddish-brown contents which are somewhat fissured. 



Clustered unicellular hairs occur on the leaves of chestnut, 

 witch-hazel, althea, European oak, etc. In European oak (Plate 

 8, Figs. 1 and 2) clusters of two and three hairs occur. The 

 walls are yellowish- white, smooth, and the tip of the hair is solid. 



In kamala (Plate 8, Fig. 3) clusters of seven or more hairs 

 occur; the walls are yellowish, and the cell cavity is reddish- 

 brown. In witch-hazel leaf (Plate 8, Fig. 4) clusters of a variable 

 number of hairs occur. The hairs, which are of various lengths, 

 have yellowish-white, thick, smooth walls, and reddish cell 

 contents. 



In althea leaf (Plate 8, Fig. 5) the hairs are nearly straight 

 and the walls are smooth. The basal portions of the hair are 

 strongly pitted. 



Branched solitary unicellular hairs occur on the leaves of 

 hesperis matronalis (Plate 7, Fig. 8), and on galphimia glauca 

 (Plate 7, Fig. 9). 



The hair of hesperis matronalis has smooth walls, and the 

 two branches grow out nearly parallel to the leaf surface. 



The hair of galphimia glauca has rough walls, and the two 

 branches grow upward in a bifurcating manner. 



MULTICELLULAR HAIRS 



Multicellular hairs are divided into the uniseriate and the 

 multiseriate hairs. Both of these groups are divided into the 

 branched and the non-branched hairs, as follows: 



1. Uniseriate. 



(^4) Non-branched. 

 (B) Branched. 



2. Multiseriate. 



(^4) Non-branched. 

 (B) Branched. 



Multicellular uniseriate non-branched hairs occur on the 

 leaves of digitalis, Western and Eastern skullcap, peppermint, 

 thyme, yarrow, arnica flowers, and sumac fruit. 



Digitalis hairs (Plate 9, Fig. 1) are made up of a varying 



