1 64 HOW TO KNOW THE MOSSES 



1. Leaves ending in a long, whitish, hair-like tip ... . 



P. piliferum. 



2. Leaves not ending in a long, whitish, hair-like tip 



.... P. juniperinum, 

 P. strictum. 

 b. Leaves yellowish-green to olive or dark green; leaf- 

 margins not folded in. (Plate VII, Fig. 3.) 



1. Capsule cylindrical .... 



P. alpinum var. arcticum. 



2. Capsule angled .... P. commune. 



P. oJnoense. 

 P. gracile. 



a. I 



Polytrichum piliferum Schreb. (Plate VII, Fig. 2) 

 is the smallest Polytrichum, with stems usually not 

 more than i inch long, and leaves and capsule much 

 smaller than in the other species. It is very common on 

 gravelly soil and around the edges or in the hollows 

 and crevices of rocks and ledges. The leaves are a 

 rather dark green, crowded at the end of the stem, and 

 end in a long, whitish, hair-like tip, which gives the 

 plants a hoary appearance. (Plate VII, Fig. 2a.) The 

 margins of the leaves fold in, but this character is not 

 easily seen in this small species. (Plate VII, Fig. 2b.) 

 The capsule is angled, erect at first, and finally becom- 

 ing horizontal or drooping. The operculum is red or 

 orange, with a short beak. The plants fruit abun- 

 dantly and are conspicuous in the spring with the red 

 fruit-stalks and pale-yellow hoods that cover the fruit. 



