236 BULLETIN OF THK UNIVERSITY OF WISCONSIN, 



Annulus none. 

 Leaves denticulate or sharply serrulate all around. 

 Perichjetial leaves abruptly pointed . . . B. Idahense, 410. 

 Perichajtial leaves gradually acuminate B. sub-erythrorrhizon, 461. 



Leaves serrate or denticulate above . \ \' erythrorrhizoD, 4G6. 



I B. digrastrnm,' 45.S. 



n. Seta rough. 



* Cilia rudimentary {1 or S), or none. 



Seta rough at the base only, costa vanishing . . B. Fendleri, 340. 

 Seta rough above only, costa percurrent . . B. populeaiu, 345. 



* * Cilia well developed and ajipendiculate. (* * *) 



Leaves serrate or denticulate. 

 Costa percurrent or nearly so. 



Seta rough throughout B. reflexum,* 342. 



Seta faintly rough above B. nanopes, ^77. 



Costa vanishing far bolow the apex. 



Alar cells quadrate, enlarged, few . . . B. Starkei," 341. 



Alar cells quadrate, numerous . . . B. (Bdipodiiim,* 342. 



Alar cells oblong hexagonal, similar to basal B. rutabiiliforme, 486. 



Leaves entire B. plumosuui, 345. 



* * * Cilia well develoj)ed but not appendicidate. 



Seta rough below only, capsule suberect . . B. Hillebraudi, 340. 

 Seta rough above only, capsule cernuous or arcuate B. campestre, 344. 

 Seta rough throughout. 

 Cells of basal angles of leaves scarcely different. 

 Leaves scarcely or abruptly acuminate, dioicous. 

 Very short acuminate, glossy, not decurrent B. rivulare,* 344. 



Longer acuminate, not glossy, decurrent B. Novaj-Aiig^liae,^ 344. 



Leaves gradually acuminate, autoicous. 

 Lanceolate to ovate-lanceolate, sub-falcate secund B. Yelntiuum, 339. 

 Ovate to ovate-lanceolate, straight, spreading. 

 Capsule without evident collum . . B. rntabulum,^ 342. 



1 1 am unable to obtain from the descriptions any characters which v?iU separate these 

 two species. 



' See Aj)pendix, nos. 479, 4S0. 



*£. curtiim Lindb. (Appendix, no. 482) falls here, if it is not identical with B. cedipo- 

 dium. 



* See Appendix, no. 474. 



* See Appendix, no. 471. 

 ' See Appendix, no. 485. 



