OF WESTERN PENNSYLVANIA 319 



Over earth, stones, and rotten wood and humus, in woods ; 

 from Nova Scotia to Manitoba and southward to Missouri and 

 Maryland. Rare in our region. 



McKean : D. A. Burnett. (Porter's Catalogue). 



4. Isopterygium geophilum (Austin) Jaeger. 



(Rhynchostegiuin geophilum Austin ; Plagiothecium geophilum 



Grout; Hypnum depressum Sullivant and Lesquereux). 



Dark green, very glossy, thinly, softly, and loosely 

 matted : stems prostrate, irregularly divided, more or less com- 

 pressed ; leaves flat, distichous, rather distant, widely spread- 

 ing, oblong-lanceolate, gradually and symmetrically narrowed 

 to a somewhat blunt apex, serrate above, rounded at the base, 

 non-decurrent ; costa short, double, rather distinct ; median 

 leaf-cells linear, prosenchymatous, flexuous, about 8-12:1, a 

 few alar sub-rectangular, hyaline, only a little enlarged and 

 not forming a distinct auricle : capsule small, ovate, gibbous, 

 thin-walled, unsymmetric, inclined ; peristome normally 

 hypnoid, teeth yellowish, segments narrow, linear, the cilia 2 

 or 3, some as long as segments; annulus large, 2-seriate; lid 

 conic, obliquely long-rostrate. 



On moist earth or stones, usually near water in lowlands ; 

 occurring from New York to Wisconsin and south to Mary- 

 land. Rare, — in our region reported but once. 



Cambria : Cresson. T. C. Porter. (Porter's Cata- 



logue). 



5. Isopterygium pulchellum variety nitidulum (^Vahlenberg) 



Brotherus. 

 {Hypniim pulchelluin var. nitidulum Lesquereux and James ; H. 



iiitidum Weber and Mohr; Leskea nitidula Wahlenberg). 



Slender, in prostrate and straggling tufts, bright glossy 

 metallic green : stems creeping, usually not much more than 1 

 cm. long, complanately branched, the branches numerous and 

 slender; leaves sub-distichous, about 1 mm. long, more or 

 less falcate, very glossy, hardly altered when dry, entire, 

 plane-margined, narrowly lance-ovate, from near the base 

 gradually narrowed to a long and slender acumen, the base 

 rounded but not decurrent nor excavate; costa usually none; 

 median leaf-cells narrowly linear, about 15-25 :1, .005-008 mm. 

 wide, pointed, the basal sub-oval and wider and shorter but 

 not differentiated otherwise at the angles : seta reddish, slender, 

 about 1.5-2 cm. long; capsule small, rather variable, ranging 

 from oblong and tapering below into the neck to short and 

 ovoid, and from erect and symmetric to curved and more or less 

 horizontal, when dry usually wide-mouthed and constricted 

 below the rim, ranging from greenish-brown when young to 

 castaneous when old; lid conic, apiculate; peristome-teeth 



