356 BULLETIN OF THE UNIVERSITY OF WISCONSIN. 



late; costa double, short; cells minute, indistinct, narrowly elliptic, pale, 

 slightly papillose, alar quadrate; perichaetial leaves lanceolate- acuminate, 

 longer, secund, concave, longitudinally plicate, ecostate; yellowish: seta 

 yellowish-red, ascending; capsule horizontal, minute, asymmetric-cylin- 

 dric, strongly constricted in middle, gibbous or strumose at base, wide- 

 mouthed, brown; lid minute, short apiculate: peristome teeth very prom- 

 inent, connivent when wet, red, strongly cristate, segments yellow, smooth, 

 broad, carinate, imperforate, cilia solitary, broad, shorter and paler. 

 Hypnum homalostegium Mtiller, Flora 56: 484. 1873. Trunks of trees, 

 West Fowl River, Alabama. 



537. Hypnum Sommerfeltii Myr. Stems 15-30 mm. long, delicate, de- 

 pressed, irregularly divided or sub-pinnate, branches ascending; tufts green 

 or yellowish: leaves crowded, very spreading, sometimes sub-secund at ex- 

 tremity of branches; stem leaves broadly oval-lanceolate, long acuminate, 

 denticulate below, ecostate or faintly bicostate; branch leaves oval lanceo- 

 late; basal cells quadrate or rectangular, forming yellowish auricles, others 

 linear, broader than in If. Halleri; inner perichaetial leaves oblong, 

 plicate: capsule sub -horizontal, oblong sub-cylindric, arcuate, contracted 

 below mouth; lid convex conic; annulus large: monoicous. Husnot, Muse. 

 Gall. 364. On old logs, bases of trees, damp rocks and earth: Canada; 

 British Columbia. 



538. Hypnum byssirameum C. M. & Kindb. Resembling a small form 

 of H. Sommerfeltii, but leaves denticulate all around: barren. Mac. Cat. 

 323. On the base of a dead tree, Ontario. 



539. Hypnum Macounii Kindb. Allied to //. Mspidulum: habit of 

 the European If. Halleri: monoicous: plants small, interlaced in dense 

 brownish green tufts: stems pinnate, prostrate, sparingly radiculose: leaves 

 densely crowded, squarrose-recurved, round deltoid, short acuminate, re- 

 flexed on borders of entire base to denticulate acumen; alar cells quadrate, 

 pellucid, not numerous, others short oblong or short lanceolate; costa obso- 

 lete or none: capsule small, narrow cylindric, slightly curved; annulus simple; 

 basilar membrane low; lid convex, obtuse, not apiculate; pedicel reddish 

 brown, smooth. Mac. Cat. 224. On earth and rocks: British Columbia; 

 Rocky Mountains. 



540. Hypnum unicostatum C. M. & Kindb. Differs from H. chrys- 

 ophyllum in dense tufts: stems more irregularly branching, creeping: 

 leaves shorter-acuminate; alar cells smaller, not yellow; costa more dis- 

 tinct; perichaetial leaves gradually acuminate-subulate or filiform pointed 

 with acumen arcuate: capsule smaller. Mac. Cat. 224. Canada. 



541. Hypnum decursiyulum C. M. & Kindb. Differs from H. chrys- 

 ophyllum in leaves decurrent with broader base, borders recurved at 

 angles; alar cells numerous, hyaline: barren. Mac. Cat. 224. On old logs: 

 British Columbia; Newfoundland. 



