OF WESTERN PENNSYLVANIA 30S 



ly incrassate and porose, parenchymatous in Jihe mostly some- 

 ^yhat excavate angles; inner perichaetial leaves plicate, lance- 

 subulate : seta long, drying twisted ; cap§i>le cernuous to hori- 

 zontal, rarely erect, oblong to cylinidric, arcuate or rarely 

 straight, mostly smooth and annulate; lid convex-conic, um- 

 bonate to apiculate or sometimes short-rostrate. 



A genus of about 115 species, mainly confined to the teni- 

 perate regions; at least 40 species occur in North America; 

 about 11 species in our region. 



Key to the Species. 

 a. Leaves not falcate nor secund. b. 



a. Leaves falcate or secund. c. 



b. Leaves entire. 8. S. haldanianus. 



b. Leaves distinctly serrulate, at least towards the apex. 



(S. nemorotts (Koch) 

 Lindberg) . 

 c. Leaves usually distinctly entire. d. 



c. Leaves serrulate, at least towards the apex. 



f. 

 d. Distinctly regularly pinnate. 6. 5. arcuatus. 



d. Not distinctly regularly pinnate. e. 



e. Perichaetial leaves plicate; alar leaf-cells strongly inflated. 



7. 5". pratensis. 

 e. Perichatial leaves not plicate; alar leaf-cells not strongly inflated. 



4. S. cupressiformis. 

 f. With alar cells strongly inflated. i. 



f. With alar cells not strongly inflated. g. 

 g. Stems not regularly pinnate; leaves usually entire. 



4. vS". cupressiformis. 

 g. Stems regularly pinnate; leaves serrulate, at least above. 



h. 

 h. Alar leaf-cells not inflated: capsule strongly arcuate. 



1. 5. reptilis. 

 h. A few alar leaf-cells somewhat inflated: capsule more or less 

 symmetric. 3. S. imponens. 



i. More or less regularly and evenly pinnate, k. 

 i. Not regularly pinnate. j 



j. Lid altogether about as long as the urn. 



9. 5. recurvans. 

 j. Lid altogether about one-half as long as the urn. 



10. S. delicatulus. 

 k. Slender and sparsely branched: lid altogether about one-half as 

 long as the urn; cilia rudimentary or none. 



U. S- tenuirostris. 

 k. More robust and more abundantly branching: lid relatively short; 

 cilia well developed. 1.- 



1. Capsule when dry and empty smooth to sub-costate; spores 



about .01S-.018 mm. 2. S. fertilis. 



1. Capsule when dry and empty strongly plicate; spores about 

 .019-.023 mm. S. S. curvifolius. 



1. Stereodon reptilis (Richard) Mitten. 

 (Hypnum reptilis Richard). 

 (Plate XLV) • 

 Small, dark or yellowish-green, lustrous, widely and loose- 

 ly cespitose : stems more or less regularly pinnate but not 



