OF WESTERN PENNSYLVANIA. 17 



74. Calyptra conical-campanulate; cap- 

 sule immersed: segments linear or 



very narrow-carinate ( Cryphaea) 



75. Ecostate Leucodon, p. 214 



75. Costate Forsstroemia, p. 216 



76. Leaves mostly rough-papillose. 77 



76. Leaves smooth, or sometimes 

 slightly papillose at the cell- 

 angles 89 



77. Capsule erect and symmetric 78 



77. Capsule usually arcuate, unsymmetric. 84 

 78. Leaves costate, margin usually en- 

 tire 79 



78. Leaves ecostate 83 



79. Costa not more than half the length of 



the leaf Haplohymenium, p. 241 



79. Costa strong, nearly reaching the apex 



of the leaf 80 



80. Primary stems stoloniform, sec- 

 ondary stems bearing the sporo- 

 phytes; stem-leaves minute; para- 



phyllia none Anomodon, p. 242 



80. Primary stems bearing the sporo- 

 phytes and not stoloniform; branch 

 and stem leaves not markedly dis- 

 similar; paraph)- Ilia often present 81 

 81. Paraphyllia none; leaf-cells compact, 

 round-hexagonal, nearly smooth; cilia 

 none; teeth without lamellae, not hygro- 

 scopic ; dioicous Leskcella, p. 251 



81. Paraphyllia present; leaf-cells hexagonal 

 to parenchymatous, mostly unipapillate ; 



autoicous 82 



82. Teeth with well developed lamellae; 



segments narrow-linear Leskea, p. 248 



82. Teeth with low lamellae; segments 



none Lindbergia, p. 247 



83. Cilia two; plants glaucous-green with 

 closely imbricated leaves and julaceous 



branches Myurella, p. 240 



83. Cilia none; plants light green with loose- 

 ly appressed leaves and more or less 



flattened branches Schwetschkeopsis, p. 223 



84. Plants creeping, one-to three- 

 pinnate 85 



84. Plants erect to ascending, simply 



pinnate, in large tufts 88 



85. Plants small, to 20 cm., delicate, one-to 



two-pinnate 86 



85. Plants larger, to 10 cm., one-to three- 

 pinnate; in large flat mats Thuidium, p. 256 



86. Costa of stem-leaves one-fifth to 

 one-sixth of the width of the leaf 



base Thuidium, p. 256 



86. Costa of stem-leaves one-tenth to 

 one-twelfth of the width of the leaf 



base 87 



87. Stem and branch leaves dissimilar: leaf- 

 cells each with several minute papillae.. Rauia, p. 252 



