THE POLYTRICHACE.E OF WESTERN NORTH AMERICA 325 



10. Polytrichum strictum Banks, in MSS. 



Polytrichum behringianum Kindb., 30 in Rev. Bryol. 1894, p. 39. 



Strictum = drawn tightly; probably referring to the closely ap- 

 pressed leaves in the dry plant. 



Plants 6-20 cm. tall, densely tufted, rigid, almost terete when dry 

 with its closely appressed leaves. Stems more slender than in P. 

 juniperinum, usually covered for the greater part of its length 

 with dirty-white tomentum, slightly branched. 



Leaves erect-patent, shorter and narrower than in P. juniperinum, 

 straight, closely and regularly imbricated when dry. Margin in- 

 curved, entire. Lamellae 25-35, 4~7 ce Us high; marginal cells longer 

 than wide, ovate or flask-shaped, smooth. Vein excurrent in a red 

 dentate arista. 



Calyptra covering the capsule. 



Capsule sharply 4-angled, cubic or very little longer than wide; 

 hypophysis short. Pedicel 4-6 cm. long. On soil. From Kotzebue 

 Sound north of Bering Strait southward along the coast to British 

 Columbia; Cascade and Rocky Mountains of British Columbia; 

 northeastern North America; Greenland; Europe; Asia; Argen- 

 tine Republic. 



11. Polytrichum hyperboreum R. Br., in Parry, Voy. Suppl. p. 



294, (1824). 

 Polytrichum boreale Kindb., in Laubm. Schwed. U. Norw. (1883). 



Name derived from hyper = beyond, and boreas = the north 

 wind; referring to its arctic habitat. 



Plants dioicous, 3-12 cm. high. Stems simple or branched, 

 branches in tufts. 



Leaves spreading when moist, appressed when dry. Margin 

 broad, incurved, entire. Lamellae more or less crenulate, 5-7 cells 

 high, 25-35; marginal cells ovate or flask-shaped, higher than wide, 

 smooth, larger than the others. Vein excurrent in a very thick, 

 short, hyaline, slightly serrate arista. 



Capsule erect or inclined, sharply 4-angled, papillose, about if 

 times as long as wide; hypophysis flattened, deeply constricted from 



30 A comparison of authentic Polytrichum behringianum with Polytrichum strictum 

 shows them to be the same. 



