OF WESTERN PENNSYLVANIA 161 



Usually near streams on shaded banks or in crevices of 

 rocks where moist, in Europe, northern Asia, and, in North 

 America, from Anticosti to Alaska and south to northern 

 United States. 



Allegheny : Schenley Park, Pittsburgh, September 15, 



1905. O. E. J. 



AIcKean : Hawkins and Quintuple, August 2, 1895. 



D. A. B. (Figured). ; 



Washington : On shale cliff in narrow ravine, Hanlin, 

 May 21, 1908, and N. Branch Maple 

 Creek, Charleroi, April 24, 1908. O. E. J. 

 4. Mnium spinulosum Bryologia Europxa. 



Similar in many respects to Mniuni serratum, the leaves 

 obovate to spatulate at the apex of the stem, clustered above, 

 decurrent, acute, sharply doubly serrate on the thickened red- 

 dish border in the upper two-thirds ; costa percurrent, not 

 dorsally toothed, often ending below the apex in the lower 

 and middle leaves ; leaf-cells about .020-030 mm., angled hexa- 

 gonal, or below rectangular, incrassate, non-collenchymatous : 

 synoicous : sporophytes either single or clustered ; seta erect ; 

 capsule horizontal or inclined, ovate-oblong, light yellowish, 

 the peristome forming a prominent red border at the mouth ; 

 operculum rostrate. 



On the ground in evergreen woods, usually in mountain- 

 ous or hilly regions. Europe and northern North America, 

 from Nova Scotia to Alaska and south to the northermost 

 United States. It is reported from eastern Pennsylvania and 

 from Ohio but not yet from our region. 



5. Mnium rostratum Schrader, Schwaegrichen. 



(Astrophylluin rostratum Lindberg). 



Large, loosely cespitose, stoloniferous : stems erect, short, 

 the sterile shoots creeping or arched ; leaves broadly oblong 

 or slightly obovate, rounded at both ends, tapering but little 

 at base, at the apex very broadly rounded or almost truncate, 

 short apiculate, the border strong, brownish, serrate in the 

 upper half with a single row of short obtuse or almost obsolete 

 teeth ; the comal leaves large, up to 5 mm. long, those of the 

 sterile shoots complanate-two-ranked ; costa excurrent in the 

 short apiculus; leaf-cells incrassate, collenchymatous, about 

 .025-030 mm., rounded-hexagonal, not radiating in rows from 

 the costa as in affine var. ruguuin, which in the sterile condi- 

 tion it closely resembles : capsules usually 1-3, clustered, sub- 

 pendulous to horizontal, yellowish, operculum long rostrate; 

 peristome-teeth yellowish, the inner peristome orange: synoi- 

 cous : mature in spring. 



On wet rocks and earth in woods: almost cosmopolitan 

 in the temperate zones, in North America from central and 



