182 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



II. Monoicous, eradiculose, costa vanishing, guides 



present. (Ill) . .... * , , , . D. molle, 66. 



III. Dioicous, stems subradiculose above, costa very broad, %-4-strat- 



ose, superficial cells thin, without chlorophyll, 

 capsule erect, regular. (IV.) 



Costa one-half leaf -width at base. 



Costa not furrowed at back, smooth D. albicans, 71. 



Costa furrowed and toothed at back . D. longifolium, 70. l 



Costa one-fifth to one-fourth leaf-width at base . . D. Sauteri, 68. * 



IV. Dioicous, stems radiculose, often densely so, costa with median 



guides. 



A. Capsule cernuous, more or less arcuate. 

 i. Leaf cells pitted. 



a. Costa not reaching apex, leaves mostly transversely undulate. 



Leaf cells above elongated. 



Costa serrate at back, not lamellose D. Bonjeani, 74. 3 



Costa with serrate lamellae. 



Capsules clustered, perichaetial leaves differentiated D. undnlatum, 76. 

 Capsules solitary (?), perichaetial leaves like 



others D. dipteroneuron, 75.* 



Capsules solitary, perichaetial leaves tubulose, abruptly 



narrowed D. Bonjeani, 74. 3 



Leaf cells above isodiametric. 



Margin smooth to near tip .... D. brachycaulon, 88. 

 Margin serrate or denticulate. 

 Upper costa and lamina rough at back. 



Capsules clustered, leaf margins sharply serrate D. Drummondii, 76. 

 Capsules solitary, leaf margins finely denticu- 

 late above widened base . . . . D. spurium, 75. 

 Costa and lamina smooth at back, capsules solitary, 



margins irregularly denticulate in upper half D. Bergeri, 75. 6 



1 See Appendix, no. 67. 



8 See Appendix, no. 68. 



8 D. palustre La Pyl., L. & J. Man. See Appendix, nos. 85-87. 



4 Ex descr. probably =D. Bonjeani DeNot. 



*D. Schraderi W. & M., L. & J. Man. 75. 



