20 A MANUAL OF MOSSES 



107. Alar cells parenchymatous Drepanocladus, p. 280 



107. Alar cells prosenchymatous 108 



108. Leaf-cells prolonged-linear Calhergon, p. 284 



108. Leaf-cells prosenchymatous-hexa- 



gonal, 2 to 6 times as long as wide. Hysroatiiblystegtuiii,p.2ys 

 109. Leaves cordate-to ovate-lanceolate, 



more or less acuminate; costa weak, end- 

 ing at or beyond the middle of the leaf; 



cells rarely linear, mostly quadrate and 



parenchymatous, or hexagonal and pros- 

 enchymatous imhlystegium, p. 264 



109. Not with the above combination of char- 

 acters 110 



110. Leaf-cells narrowlj' linear; leaves 

 broadly ovate or cordate, prolonged 

 into awl-shaped reflexed squarrose 

 tips Campylium, p. 290 



110. Not with above combination of 



characters Ill 



111. Leaves oval- to oblong-lanceolate, more 



or less long acuminate; leaf-cells narrow, 



prosenchymatous; plants shining Homomallium, p. 274 



111. Not with characters combined as 



above 112 



112. Plants very slender, not shining; 

 leaves usually spreading in all di- 

 rections, lanceolate to linear-lanceo- 

 late; cells rhomboidal to long hexa- 

 gonal, 2 to 4, or rarely 6-8, times 

 as long as broad Amblystegiella, p. 272 



112. Leaf-cells prolonged-linear, most- 

 ly very narrow 113 



113. Leaves erect-spreading or imbricated, 



oblong-ovate to nearly circular, obtuse 



or apiculate, often very concave; costa 



short and double, or none icrocladiuiii, p. 286 



113. Leaves more or less falcate-secund to 



circinate, from a mostly narrowed and 



somewhat decurrent base, becoming 



ovate- to triangular-or cordate-lanceo- 

 late, more or less slenderly acuminate; 



costa weak and reaching above the 



middle, or rarely even excurrent Drepanocladus, p. 280 



114. Paraphyllia numerous; leaves more 

 or less erect, from abruptly to 

 gradually acuminate, mostly plicate. Hylocomium, p. 2gS 



114. Paraphyllia none or very few... 115 

 115. Stem-leaves more or less squarrose- 



spreading to secuud, acuminate 117 



115. Stem-leaves more or less crowded, im- 

 bricate, but with more or less spreading 



or secund tips 116 



116. Stem-leaves turgidly imbricate and 

 secund, rugose, narrowly lanceolate- 

 acuminate from a broadly oblong 

 base, glossy; apex distinctly serrate; 

 cilia two; annulus present Rhytidium, p. 297 



116. Stem-leaves close or loosely im- 

 bricate, not secund, broadly ovate 



