OF WESTERN PENNSYLVANIA 249 



low, segments linear, carinate, as long or shorter than the 

 teeth, cilia rudimentary; Hd acute-conic; calyptra cucullate, 

 glabrous ; spores small. 



A widely distributed genus of about 20 species ; 7 species 

 in North America ; 3 in our region. 



Key to the Species. 



a. Leaves more or less secund, lance-ovate: capsule sometimes 

 slightly curved. 1. L. polycarpa. 



a. Leaves not secund, ovate, acute to obtuse; capsule erect, straight. 



b. 

 b. Leaves two-plicate, symmetric, the margin often revolute. 



2. L. gracilescens. 

 b. Leaves non-plicate, unsymmetric. plane-margined. 



3. L. obscnra. 



1. Leskea polycarpa Ehrhart, Hedwig. 



(Z,. polycarpa Ehrhart; Hypnuin medium Dickson). 



Slender, thinly tufted : stems prostrate, pinnately to bi- 

 pinnately branched, 2-4 cm. long, with short curved or erect 

 branches, intricately matted into close but thin patches ; leaves 

 erect-spreading to secund, loosely appressed-imbricate when 

 dry, about 0.4X10 mm., lanceolate and gradually acute from a 

 slightly decurrent, sub-cordate, more or less ovate base, entire, 

 usually two-plicate, acute to acuminate; costa ending a little 

 below the apex ; median leaf-cells thin-walled, pellucid, more 

 or less dorsally papillose, hexagonal, about .007-008 mm. wide, 

 with one or two papillae on each surface ; branch-leaves smaller 

 and more obtusely, pointed : seta about 1 cm. long, reddish ; 

 capsule cylindric, narrow, basally tapering, straight or almost 

 so, reddish-brown, constricted below the mouth when dry; lid 

 elongate-conic, acute; peristome-teeth long, whitish, narrowly 

 linear, connivent when dry, the segments about as long, from 

 a low basal inembrane narrowly linear, scarcely carinately 

 split; cilia rudimentary or none; spores mature in early 

 summer. 



On roots, bases of trees, stones, or decaying wood in wet 

 situations; Asia, and from Newfoundland to British Columbia 

 and southward. Not yet found in our region. 



2. Leskea gracilescens Hedwig. 

 (L. obscura Lesquereux and James, p.p.; Hypniim gracilescens 



Beauvois). 



Intricately cespitose in thin mats : stems prostrate, pinnate- 

 ly branched with numerous simple, erect, somewhat julaceous 

 branchlets ; paraphyllia usually few, lanceolate ; stem-leaves 

 erect-spreading when moist, appressed-imbricate when dry, 

 about 0.4-0.5x0-7-0.9 mm., ovate, acute or somewhat acumi- 

 nate, entire, margins more or less revolute, sometimes more 

 quickly tapering to a blunt point, somewhat bi-plicate; costa 



