THE POLYTRICHACE.E OF WESTERN NORTH AMERICA 303 



4b. P, alpinum var. brevifolium 19 Brid., in Sch. Syn. I. ed. p. 



441, (1860). 

 Polytrichum alpinum var. brevifolium Muell., in Syn. I, p. 210, (1849). 



i. Leaves about 7-8 mm. long. 

 2. Leaf-sheath to blade about .as 1:3-3?. 

 3. Plant about 4 cm. tall or shorter. 

 4. Capsule 3-4 mm. long. 



5. Width of capsule to length as i :i-2i. 

 6. Stems with few* and short branches. 

 7. Pedicel 2^-3^. cm. long, 

 a. Capsule with distinct neck. 



On rocks. Islands of Bering Sea; Mt. Dana, California; Hudson 

 Strait; Greenland; mountains of Europe; Siberia. 



4c. P. alpinum var. septentrionale 20 (Sw.) Brid., in Sch. Syn., 



i ed., p. 44 1 (1860). 

 P. alpinum var. microdontium? 1 Kindb., in Mac. Cat. Vol. 6, p. 



152, (1892). 



i. Leaves about 7-8 mm. long. 

 2. Leaf-sheath to blade about as 1 13-34. 

 3. Plants about 5 cm. tall or shorter. 

 4. Capsule 3-4 mm. long. 



5. Width of capsule to length as i :iJ-2^. 

 6. Stems simple. 



7. Pedicel 1^-2 cm. long, 

 a. Capsule without distinct neck. 



On soil and rocks. Islands of Bering Sea; Kodiak Island, 

 Alaska; mouth of Skeena River and Rocky Mountains, British 

 Columbia; Europe. 



4d. P. alpinum var. arcticum 22 (Sw.) Brid., in Sch. Syn. i ed* 



p. 441 (1860). 

 Polytrichum sylvaticum Menz., in Trans. Linn. Soc. 4. p. 83, n. 



19 (1798). 

 Polytrichum alpinum var. arclicum Wahl., in Fl. Lapp., p. 346 



(1812). 



19 Breve = short, folium = leaf; because its leaves are shorter than those of nearly 

 all other varieties. 



20 Septentrionale = pertaining to the north; referring to the northern habitat of 

 this variety. 



21 Examination of Alaskan collections leads to the conclusion that Cardot and Thriot 

 are right in concluding that var. microdontium does not separate from var. septentrionale- 



22 So named on account of its arctic habitat. 



Proc. Wash. Acad. Sci., August, 1910. 



