8 BULLETIN 4 



4. Leafy plants shorter (one to five inches long). Dry 



leaves usually appressed, with somewhat spreading 

 tips. Capsule smaller, rarely much exceeding an 

 eighth of an inch in length. Calyptra hairs usually 

 dirty brown, rarely reddish brown. Common, es- 

 pecially in moderately dry situations. The plant 

 which has long passed as typical Polytrichum com- 

 mune in America. Polytrichum commune, var. peri- 

 goniale (Mx.) Br. Eur. 



5. Dry leaves usually appressed, with somewhat spread- 



ing tips. Generally growing in very damp situa- 

 tions. Rare. The typical European Polytrichum 

 commune L. 



5. Dry leaves abruptly and widely speading from the 



base. Otherwise much as in the preceding, though 

 the capsule may occasionally be smaller and the 

 leaves slenderer. In wet situations. Rather rare. 



Polytrichum commune, var. uliginosum Hueb. 



6. Leaves prolonged into a whitish or transparent hair- 



like tip. Common on sandy or sterile soil. Poly- 

 trichum piliferum Schreb. 



6. Leaves not prolonged into a transparent hair-like tip. . . 7 



7. Leaves loosely appressed when dry, typically more 



than a quarter of an inch long. Frequently in dry 

 or moist situations. Polytrichum juniperinum Willd. 



7. Leaves short (less than a quarter of an inch long), 

 closely appressed when dry, forming slender strict 

 shoots. Stems tomentose below. In wet places, 

 peat bogs, etc.; smaller and more compact on the 

 mountains. Polytrichum strictum Banks. 



