THE POLYTRICHACE^ OF WESTERN NORTH AMERICA 303 



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



441, (i860). 

 Polytrichum alpinum var. hrevifolium 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 j-2^. 

 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^" (Sw.) Brid., in Sch. Syn., 



I ed., p. 44i (i860). 

 P. alpinum var. microdontium-^ Kindb., in Mac. Cat. Vol. 6, p. 



152, (1892). 



I. Leaves about 7-8 mm. long. 



2. Leaf-sheath to blade about as i :3-3^. 

 3. Plants about 5 cm. tall or shorter. 

 4. Capsule 3-4 mm. long. 



5. Width of capsule to length as i :i^-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^^ (Sw.) Brid., in Sch. Syn. i ed- 



p. 44T (i860). 

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



19 (1798). 

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

 (1812). 



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

 all other varieties. 



2" 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 Theriot 

 are right in concluding that var. microdoiilium does not separate from var. septenlrionale- 



^ So named on account of its arctic habitat. 



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



