204 American Midland Naturalist Monograph No. 6 



1. Leskea polycarpa Ehrhart, Hedwig 

 (L. polycarpa Ehrhart; Hypnum 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; central strand distinct; leaves erect-spreading to secund, 

 loosely appressed-imbricate when dry, about 0.4x1.0 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 sur- 

 face; 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 short-conic, acute; 

 peristome-teeth long, whitish, narrowly linear, connivent when dry; segments 

 about as long, from a low basal membrane 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.; Hypnum gracilescens Beauvois) 



Intricately cespitose in thin mats: stems prostrate, pinnately branched with 

 numerous simple, erect, somewhat julaceous branchlets; central strand indis- 

 tinct or none; paraphyllia usually few, lanceolate; stem-leaves erect-spreading 

 when moist, appressed-imbricate when dry, about 0.4-0.5 x 0.7-0.9 mm, ovate, 

 acute or somewhat acuminate, entire, margins more or less revolute, some- 

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

 percurrent; branch-leaves hardly different but scarcely plicate; median leaf- 

 cells usually uni-papillate on dorsal surface, smooth on ventral, quadrate- 

 hexagonal, about .008-.010 mm, the apical more rounded, the basal somewhat 

 quadrate; capsule erect, basally tapering, oblong-cylindric; peristome-teeth 

 whitish, lance-linear, lamellate, about 0.4 mm long; the linear segments shorter, 

 carinate, sometimes more or less rudimentary; basal membrane I/4 as high as 

 teeth; cilia none; lid conic, acute to obtuse; spores mature in summer. 



On the base of trees, roots, and on rotten logs, etc.; from eastern lower 

 Canada to the Gulf States and westward to the Rocky Mountains. Common- 

 est in northeastern United States. Reported from Middle Wheeling Creek, 

 W. Va., A. J. Sharp and Miss Gail Holliday, June 11, 1935; and: 



Washington Co.: Linn and Simonton. (Porter's Catalogue). 



3. Leskea obscura Hedwig 



{L. nervosa Sullivant; L. microcarpa Schimp)er) 

 Plates XXXIX, LXVII 



Small, loosely and intricately cespitose, dark green: stems prostrate, rather 

 irregularly divided, sparingly branched, the branches short, plump, erect; cen- 



