Hypnum.] BRYACE^. 377 



cially at the base ; outer perichsetial leaves spreading from the 

 middle, tlie inner longer, erect, narrowly acuminate and costate, 

 bistriate : capsule incurved, subliorizontal, oval or cylindrical- 

 oblong, arcuate when dry, light brow^n, often of two colors; 

 operculum large, orange, conical-apiculate ; peristome large ; 

 teeth dark orange ; cilia two or three, appendiculate, as long as 

 the segments, which are entire or slightly cleft; annulus com- 

 pound. — Spec. PL 11'29. Amhlysteyiuni riparium., Bruch tfc 

 Sell imp. Bryol. Eur. t. 570, 571. Stereodon rijxirius, Mitt. 



Var. abbreviatum. Stems short: leaves small, more com- 

 pact : cajjsule sliorter. 



Var. flaccidum. Small ; stems filiform, very long ; branches 

 and branchlets flat, soft, divergent: leaves distant, sagittate- 

 lanceolate, long-acuminate : pedicel short and capsule small. 



Var. fluitans. Stems and branches long, soft, dirty yellow : 

 leaves closely imbricated : rarely fertile. 



Hab. Stones, decayed wood, and roots of trees, in swamps and stag- 

 nant water, especially var. flaccidum ; borders of streams, floating in 

 the mud, \a,v. fluitans; very common on both slopes of North America. 



Only the more marked American forms of this polymorphous species 

 are given here. Its small states resemble H. serpens, larger it is much 

 like H. fluitans, and in streams it resembles Fontinalis hiforniis. 



128. H. vacillans. Plants intricate, closely cesj^itose; 

 stems jirocuinbent, sparingly subpinnately brandling : stem- 

 leaves more distant, two-ranked, erect-spreading, narrowly 

 lanceolate-acuminate, those of the branches narrow, oblong- 

 lanceolate, acute or blunt at the apex ; costa stout, three-fourths 

 of tlie length of the leaves; cells narrow, irregular at the apex, 

 broadly quadrate and pellucid at the angles : capsitle suberect, 

 rugose ; operculum conical, obtuse ; cilia rugulose, shorter than 

 the segments ; annulus simple, narrow. — Amblystegium vacil- 

 la?is, Sidliv. Icon. Muse. Suppl. 96, t. 72. 

 Hab. White Mountains (Oakes). 



SuBGEj^us XVII. CAMPYLIUM. 



Stems prostrate, with crowded ascending branches. Leaves 

 abruptly long-acuminate from a broad ovate base, subsquarrose, 

 scarcely costate ; areolation minute, linear, flexuous. Capsule 

 subarcuate, often of two colors; pedicel smooth. Operculum 

 convex-conic. — Campylium^ Mitt. 



