BARNES — NORTH AMERICAN MOSSES. 245 



Dioicous, profusely branched, 



5-10 cm. long, variegated or dark purple, stolons 



green H. saruientosum, 403. 



15-30 cm. long, bright to yellowish green . . H. giganteum, 403. 

 Costa reaching middle. 



Branches irregularly pinnate, leaves spreading H. Richardsoni, 404. 



Branches few, leaves imbricate . . . H. stramineum,' 405. 



* * Cells not enlarged at the basal angles. 



Leaf margin serrulate above, leaf cells short . H. occidentale, S98. 

 Leaf margin entire, leaf cells vermicular, bordered by a 

 row of short cells. 



Leaves open H. arcticnm, 400. 



Leaves closely imbricate H. trifarium, 405. 



B. Costa very short or none or double. 



I. Alar cells abruptly enlarged (often inflated or colored).* 

 (2 on p. 246.) 



* Operculum short rostrate. 



Leaves entire H. Haldaniaunm,^ 397. 



Leaves sharply serrate . . . . . . H. nemorosum, 398. 



* * Operculum convex or conic. 

 Leaves falcate. 



[S. palustre hamulosum may be sought here.] 

 Scarcely costate, alar cells orange . . . H. eugyrium,* 401. 

 Costa reaching middle, alar cells hyaline . . H. ochraceum,^ 401. 

 Leaves not falcate. 

 Gradually filiform acuminate, alar cells orange. 

 Plants irregularly branched . . . H. Sommerfeltii,* 537. 

 Plants sub-dichotomously branched . . H. stellatum,' 379. 



1 See Appendix, no. 595-597. 



''Three barren species described by C. M. & Kindb. belong to this division: U.flac- 

 eum. Appendix, no. 580; M. subflaccum. Appendix, no. 581; H, pseudo-drepamuniy 

 Appendix, no. 582. 



3 See Appendix, no. 579. 



' See Appendix, nos. 59C, 591. 



^ See Appendix, no. 592. 



" See also Appendix, no. 538. 



' See Appendix, no. 543. 



