BARNES NORTH AMERICAN MOSSES. 183 



b. Costa per current or excurrent, leaves not undulate. 

 [I>. Bonjeani may be sought here.] 



Guides in two rows . v -, . . . D. majus, 74. 



Guides in one row. 



Margin serrulate to middle of leaf, back of costa lamellose. 

 Seta yellow, capsule long and narrow (1 : 5-6) D. consobrinuin. 84. 

 Seta red, capsule broader (1:4) . . . D. scoparium, 73. J 

 Margin entire to near apex, back of costa not lamellose. 



Cells above narrow (1 : 5-6) leaves brittle . . D. neglectnm, 73. 

 Cells above isodiametric, leaves not brittle D. forachycanlon, 88. 



2. Leaf cells not pitted or faintly so. 



Leaves quite entire or denticulate, subulate. 



Points very brittle, mostly broken . D. frasrilifoliurn, 73. 

 Points not broken ....... D. elongatnm, 71. 



Leaves entire, upper obtuse. 



Cells throughout elongated, thickened, pitted D. Greenland icnm, 89. 

 Cells short, quadrate above, not pitted . . D. Miquelonense, 72. 

 Leaves serrulate. 



Upper cells very irregular. 



Capsules cylindrical, striped or striated. 

 Costa at point of greatest leaf -width one-sixth or 



more . ... . . D. Mnhlenbeckii, 72. 8 



Costa at point of greatest leaf-width one-tenth or less. 

 Cells of upper third of lamina short (8-10 X 



10-17/0 . D. pallidum, 76. 



Cells of upper third of lamina narrower, larger, 



(15 X 50//) - - D. rhabdocarpnm, 73. 

 Capsules ovate-oblong, not striped or but faintly D. congest um. 72. 8 

 Upper cells regular, capsule obovate-oblong, striped D. fuscescens, 72. 



B. Capsule erect, symmetric. 

 Costa without stereids . , , . * . D. strictnm, 69. 



i See Appendix, nos. 17-83. 

 9 See Appendix, no. 74. 

 9 D. fuscescens L. & J. Man. 72 in part. 



4 D. fuscescens longiroslre and angustifolium" t Li. & J.Man. 72. See Appendix, nos. 

 70, 71. 



