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DESCRIPTION OF MEDICINAL PLANTS. 
whole chain of the Cumberland Mountains, especially where 
pines prevail ; also in laurel thickets. Notin the U. S. Dis- 
pensatory, but on the drug lists. 
MUSCI. (Mosses.) 
Polytrichum juniperinum, L. Haircap Moss. Robin’s Rye. 
A fine species of acrocarpous mosses with a peculiar rigid 
habit. The veil or calyptra which covers the operculum or 
lid of the capsule, is rough with dependent hairs, and the 
mouth of the capsule closed with a flat membrane continued 
from the tips of the teeth. The capsule is angular and fur- 
nished with a little apophysis below. It is common in dry 
woods in the mountains, as well as on the hilltops of Middle 
Tennessee. It is considered to be a powerful diuretic. 
