418 MUSCI. Ilypnum. 



Lelow the broad mouth when dry ; opercuhim conic-rostellate ; annukis simple : 

 processes shorter than the pale yellow teeth ; ciliolce solitary, very short. — Syn. ii. 

 408; Sulliv. Icon, Muse. 201, t. 123. 



On streambaiiks, West Humboldt Mountains, Nevada ( Watson) ; Fort Colville {LynlT) ; British 

 America, Dnmimond. Common in vaiious forms from California to Alaska and across the con- 

 tinent ; also ill Europe and South America. 



33. H. serpens, Linn. Densely cespitose, with simple filiform flexuose-erect 

 branches : leaves spreading, erect when dry, very small, ovate-lanceolate, narrowly 

 acuminate, entire, costate to the middle or nearly to the apex : capsule incurved- 

 cernuous, long-cylindrical, subarcuate, strongly arcuate when dry ; operculum convex- 

 conic, acute : ciliolse in pairs, ecjualling the reddish teeth. • — Hedw. INIusc. Frond. 

 iv. 45, t. 18; Engl. Bot. t. 1037. H. contextnni and H. spimdosum, Hedw. Spec. 

 t. 69, 72. Amblystegium serpens, Bruch & Schimp. 1. c, t. 5G4. 



Common in California (Bigclow), on the roots of bushes in swamps (Bolander), on the ground 

 near Crescent City (Brewer) ; mountains of Nevada ( Watson) ; and from Alaska to British 

 America, Colorado and the Atlantic States ; Europe and South America. A very variable species. 

 H. radicale, Beauv. (Schwaegr. Suppl. t. 20. Amblystegium radicate, Bruch & Schimp. 1. c, 

 t. 565), is a more robust and rigid form, with leaves nearly twice larger and more abru^itly acumi- 

 nate from a broader base. H. orthodadon, Beauv. (Sulliv. Icon. Muse. t. 122), and H. notero- 

 phituvi, Sulliv., which have been credited to the Pacific Coast, together with various other 

 sui)posed species, are considered referable to this. 



-J- +- Leaves thm and shining : areolation narrowly rliomhlc, rather loose at 

 base, rectangular at the angles. 



34. H. riparium, Linn. Creeping, in swampy places, or often in water with 

 the stems and branches much elongated, distantly and subpinnately branched : 

 leaves remote or somewhat crowded, usually distichously complanate, rarely sub- 

 secund, broadly ovate- or oblong-lanceolate, more or less long-acuminate, entire, costa 

 ceasing above the middle : capsule oblong-cylindric, cernuous, incurved : ciliolee 2 or 

 3, a third shorter than the processes. — Hedw. Muse. Frond, iv, 7, t. 3 ; Engl. Bot. 

 t. 20G0 ; Berkeley, Brit. Moss. t. 6, fig. 3. Amhbjstegium riparium, Bruch & Schimp. 

 1. c, t. 570. Amblystegium vacillans, Sulliv. Icon. Suppl. 9G, t. 72 ; Me Austin. 



Frequent in California {Bigelow, Breitrr, Bolander) ; Northeastern Nevada and \]h\\\ {Watson) ; 

 common in the Atlantic States and ranging from Greenland to Cuba, and throughout Europe. 



§ 4, Leaves smooth and shining, squarrose or usually falcate-secund, nerveless 

 or shortly 1 - 2-costate : areolation linear, usually flexuose or vermicidar : 

 'pedicels smooth : opercidum convex-conic or rostellate. — Hypnum proper, 



* Stem rootless or nearly so (except in n, 37), ascending; branches subp innate 

 with arcuate branchlets : leaves firm, falcate-secund, fil if or7nly attenuate, costate 

 beyond the middle or nearly to the apex: mostly marsh sjiecies. — Harpidium. 



-1- Dioecious. 



35. H. aduncum, Hedw. Stem erect, 2 to 6 inches long, slender, sparingly 

 branched, and subpinnate with short simple branchlets : leaves crowded, lanceolate, 

 long-acuminate, striate, subserrulate below, the stout costa reaching nearly to the 

 apex ; areolation somewhat rectangular, broader and subquadrate in the angles : 

 capsule cernuous, incurved-oblong, at length arcuate ; annulus broad, compound ; 

 operculum convex-conic: ciliolee 2 or 3, short. — Muse. Frond, iv. 62, t. 24; Fl. 

 Dan. t. 2563, 2621 ; Bruch & Schimp. Bryol. Eur. t. 605, and Suppl. Hypn, t. 1 ; 

 Berkeley, 1. c, t. 10, fig. 2. 



In swamps near San Francisco {Bolander) ; Virginia and Clover Mountains, Nevada ( Watson) ; 

 British America to the Atlantic States, in South America and through Europe. A very variable 

 species. 



36. H. exannulatum, Gumb. Distinguished from the last by its more shining 

 and more hooked-secund leaves, costate to the apex and with very narrow closer 



