260 BOTANICAL GAZETTE [ocTOBER 
Has.: On earth in moist places, at roots of trees and on decay- 
ing wood. Type locality England. 
Found all over the world. Widely distributed in North Amer- 
ica though less common than A. varium. 
Amblystegium serpens stands as the type species around which the other » 
" members of the genus group themselves. It is a remarkably variable species 
though having few well marked varieties. It is most easily confounded with 
two of its close relatives A. juratzkanum, which by many is made a var- 
iety of it, and A. varium. <A. juratzkanum is distinguished by having its 
leaves widely spreading and having its parts uniformly larger and its leaf 
cells longer at the base of the leaf. A. varium is generally a larger plant 
than A. serfens, has broader leaves, somewhat smaller cells throughout, and 
commonly has its leaves costate well towards the apex. Notwithstanding the 
differences in the well-marked forms, there are forms between them which will 
never cease to puzzle bryologists. 
AMBLYSTEGIUM JURATZKANUM Schimp. Plate XT. fig. 7. 
Synon.: Amblystegium juratzkanum Schimper, Syn. (1st ed.) 693. 1860. 
2d ed.) 710. 1876.—Milde, Bry. Siles. 327. 1869 —Hartmann, Skand. Fi. 
(roth ed.) 19. 1871.—Husnot, Musc. Gall. 358. f/. 202. 1893. Flora Batavia, 
PL. 939. 
Hypnum juratzkanum Boulay, Musc. Fr. 74. 1884. 
Amblystegium serpens juratzkanum R, duBuysson, Etude du genre 
Amblys. 18. 1889. 
Amblystegium juratzke Macoun & Kindberg, Cat. Can. Pl. 6:218. 1892. 
Amblystegium juratzke Braithwaite, Brit. Moss Fl. 3: 25. fd. 97. 1896. 
Exsiccati:  Aypnum juratzke Macoun, Can. Musc. 466. 
TYPE in herb. Schimper. 
Gametophyte bisexual, of medium size, loosely cespitose, bright 
green, becoming yellow below with age: stem slender, 2 to 4™ 
long, 120 to 180 w in diameter, cylindrical, prostrate, branched ; 
central strand smali and poorly developed or none, when present 
8 to 17 mw in diameter, composed of three to ten rows of cells; 
cortex thin, not well differentiated, of one layer (rarely two) of 
cells 8.5 to 17 w in diameter; cells of ground tissue 13 to 26 B; 
primary branches few, prostrate; branchlets numerous, erect or 
ascending: Jeaves linear lanceolate to ovate lanceolate, narrowly 
long acuminate, acumen equaling or exceeding the body of the leaf, attain- 
ing greatest width in basal fifth, serrulate to the base, costate, costa 
