OF WESTERN PENNSYLVANIA 223 



c. Basal membrane more or less prominent: leaves acuminate, mar- 

 gins plane; branches when dry strongly curved at the apex. 



4. Pylaisia. 



d. Branches complanate-leaved: peristome segments broad, and 



as long as the teeth. 1. Schwetschkeopsis. 



d. Branches julaceous: segments filiform or rudimentary. 



5. Pierygynandrum. 



1. SCHWETSCHKEOPSIS Brotherus. 



Dioicous or autoicous : slender, stiff, forming flat tufts, 

 green to yellowish-green : stem long, creeping, radiculose, 

 mostly densely and symmetrically pinnately branched; 

 branches densely complanately-leaved, obtuse, short to long, 

 ascending, simple or branched ; paraphyllia few, lanceolate or 

 orbicular, rarely filiform ; branch-leaves when dry imbricate, 

 when moist erect-spreading, non-decurrent, concave, plicate, 

 lance-ovate, acuminate to subulate-pointed, serrulate, plane- 

 margined ; costa none ; leaf-cells oblong-hexagonal, dorsally 

 papillose above, alar quadrate and numerous, chlorophyllose : 

 seta up to 7 mm. long, slender, tortuous, yellowish-red, smooth, 

 when dry twisted ; capsule mostly erect and symmetric, shortly 

 collumate ; exannulate, peristome double, teeth lanceolate, yel- 

 low, with zigzag divisural, densely transversely striate, closely 

 trabeculate ; inner peristome hyaline, basal membrane one-third 

 as high as teeth, smooth, segments about as long as teeth, 

 broad, split along keel, finely papillose, cilia rudimentary; 

 spores about .015 mm.; lid obliquely rostrate. 



Three species, on trees : one in Japan and Korea, one in 

 Nepal, and the following: 



1. Schwetschkeopsis denticulata (Sullivant) Brotherus. 

 (Leskea denticulata Sullivant). 

 (Plate XXXII) 

 Light green, soft, silky : stems usually 2-3 cm. long, some- 

 times more, irregularly branched, paraphyllia none; stem- 

 leaves erect-spreading, close, concave, ovate, somewhat decur- 

 rent, abruptly and narrowly acuminate, 0.4-0.9 mm. long, 0.3- 

 0.4 mm. wide, plane-margined, sometimes slightly striate, mar- 

 ginally undulate-denticulate ; ecostate ; apical leaf-cells dorsally 

 uni-papillate, the median oblong-oval to elongate-rhomboidal, 

 sometimes vermicular, about 4-8:1, about .005-.008 mm. wide, 

 the marginal uni-seriate and curvi-linear, the alar forming a 

 small group of quadrate incrassate cells ; branch-leaves smaller 

 and less abruptly acuminate, with more oblong and shorter 

 cells: seta yellowish-red, slender, tortuous, erect; capsiile 

 erect or nearly so, oblong, about 2-3 :1 ; operculum conic- 

 rostrate, about two-thirds as long as the urn ; peristome about 

 the same width as the teeth ; no cilia ; no annulus ; fruit rarely 

 found. 



