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PHARMACEUTICAL BOTANY 
Order 2. — Andreaeales, including the single genus Andreaea, of 
xerophytic habit, occurring on siliceous rock. 
Order 3. — Bryales, or true mosses, comprising the most highly 
Fig. no. — Hair-cap moss ( Polytrichum commune). A, male plant; B, same, 
proliferating; C, female plant, bearing sporogonium; D, same; g, gametophyte; 5, 
seta; c, capsule; o, operculum; a, calpytra; E, top view of male plant. {Gager.) 
