16 American Midland Naturalist Monograph No. 6 



82. Teeth with well developed lamellae; segments narrow-lmear Leskea, p. 20^ 



82. Teeth with low lamellae; segments none Lindbergia, p. 202 



83. Cilia two; plants glaucous-green with closely imbricated leaves and julaceous 



branches Myurella, p. 196 



83. Cilia none; plants light green with loosely appressed leaves and more or less 



flattened branches Schwetschkeopsis, p. 281 



84. Plants creeping, one- to three-pinnate 85 



84. Plants erect to ascending, simply pinnate, in large tufts 88 



85. Plants small, delicate, one- to two-pinnate 86 



85. Plants larger, one- to three-pinnate; m large flat mats Thuidium, p. 209 



86. Costa of stem-leaves one-fifth to one-sixth oi the width of the leaf base 



Thuidium, p. 209 



86. Costa of stem-leaves one-tenth to one-twelfth of the width of the leaf base 



(see also Thuidium) 87 



87. Stem and branch leaves dissimilar; leaf-cells each with several minute papillae 



Rauia, p. 206 



87. Stem and branch leaves similar; leaf-cells each with but one or rarely two 



papillae Haplochdium, p. 207 



88. Stem and branch leaves rather similar in size and shape 



(Helodium, Ivs. costate, p. 214 



{Hookeria, Ivs. ecostate, p. 215 



88. Stem and branch leaves dissimilar Rauia, p. 206 



89. Stems dendroid, upright from a creeping base; capsules clustered 90 



89. Stems prostrate or ascending with the capsules borne singly 91 



90. Cilia none; capsules erect and symmetric Climacium, p. 180 



90. Cilia well developed, appendiculate; capsules inclined, unsymmetric 



PoTOtrichum, p. 189 



91. Cilia none; capsule symmetric and erect, or nearly so (see also 120a) 92 



91. Cilia generally present and well developed; capsule unsymmetric, generally 



more or less arcuate and recurved, sometimes almost erect 9^ 



92. Branches strongly complanate; leaves cultriform Homalia, p. 188 



92. Branches not strongly complanate; leaves ovate to lanceolate 93 



93. Segments adhering to the teeth; basal membrane none or obscure 94 



93. Segments free from the teeth 95 



94. Leaves with short single costa; seta rough Homalotheciella, p. 286 



94. Costa short and double or none; seta smooth ...Pylaisia, p. 226 



95. Basal membrane broad and distinct Pylaisia, p. 226 



95. Basal membrane none or narrow 96 



96. Stem oval in cross-section; teeth of peristome not hyaline-margined 



_ Entodon, p. 191 



96. Stem rounded; teeth of peristome hyaline-margined Platygyrium, p. 229 



96. Small, slender; leaves lance-linear to lanceolate; teeth not margined; cilia 



rudimentary or none Amblystegiella, p. 223 



97. Stem mostly woody, often stoloniferous, irregularly divided, the leafy branches 

 often more or less regularly pinnate; leaves erect-spreading to squarrose, 

 rarely imbricated; cells narrowly prosenchymatous, rarely parenchymatous, 

 towards the base more lax and often punctate; costa various, but rarely 

 almost percurrent; alar cells mostly rounded or oval — 4- to 6-sided, usually 

 forming a well defined but not markedly inflated group; teeth and segments 

 same length; basal membrane wide; cilia usually well developed; operculum 



rounded, conical-obtuse to short rostrate {^Hypnaceae} 99 



97. Characters not combined as above 93 



98. Slender plants with creeping stems; leaves often secund or somewhat com- 

 planate; costa none or double and short; cells narrow, prosenchymatous; 

 alar cells 3 to 8, large, inflated and jjellucid; capsule small, oval to 

 oblong, exothecial cell-walls collenchymatous; operculum mostly long and 

 slenderly rostrate -. 



