BARNES NORTH AMERICAN MOSSES. 245 



Dioicous, profusely branched. 



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



green . . . - . . . . H. sarmentosum, 403. 



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

 Costa reaching middle. 



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



Branches few, leaves imbricate . . . H. stramineum, 1 405. 



* * Cells not enlarged at the basal angles. 



Leaf margin serrulate above, leaf cells short . H. occidentale, 598. 

 Leaf margin entire, leaf cells vermicular, bordered by a 

 row of short cells. 



Leaves open . . . . . . / . H. arcticum, 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. Haldanianum, 8 397. 



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



* * Operculum convex or conic. 

 Leaves falcate. 



[H.palustre haninlosnm may be sought here.] 



Scarcely costate, alar cells orange H. engyrium, 4 401. 



Costa reaching middle, alar cells hyaline . . H. ochracenm, 5 401. 

 Leaves not falcate. 

 Gradually filiform acuminate, alar cells orange. 



Plants irregularly branched H. Sommerfeltii, 6 537. 



Plants sub-dichotomously branched . . H. stellatum, 7 379. 



i See Appendix, no. 595-597. 



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

 cum, Appendix, no. 580; H. subflaccum, Appendix, no. 581; H. pseudo-drepanium, 

 Appendix, no. 582. 



3 See Appendix, no. 579. 



4 See Appendix, nos. 590, 591. 



5 See Appendix, no. 592. 



6 See also Appendix, no. 538. 



7 See Appendix, no. 543. 



