1897] NORTH AMERICAN SPECIES OF AMBLYSTEGJUM 247 
operculum high conic or rostellate from a conic base; annulus 
of one or two rows of cells, persistent: spores pale, minutely 
roughened, 8 to 13 in diameter: calyptra not seen. 
Has.: Growing on limestone rocks in shaded ravines, form- 
ing thin, loose patches over the substratum; in company with 
Thuidium pygmeum. Type locality, central and southern Ohio. 
Northeastern U. S.: Ohio (Sullivant), Penn., very rare. 
A very delicate pests ed confounded with A. —* and A. confer- 
voides. The leaf ch , however, should in m ses be sufficient to 
separate these three species. is A. confervoides the leaf cells are compara- 
tively short and irregular throughout, with a large number in the alar 
regions quadrate or triangular; while in A. minutissimum the leaf cells are 
much elongated throughout, with the longest cells in the middle of the leaf. 
A. sprucei, while its leaf cells are decidedly elongated throughout, is distin- 
guished from A. minutissimum by the leaves papillosely serrulate at base 
with the longest cell at the very apex. Further, both 4. confervoides and 4. 
Sprucet have the widest point of the leaf some distance above the line of 
insertion, while in 4. ménutissimum the widest point is at the line of insertion, 
in most cases. 
AMBLYSTEGIUM spRUCEI (Br.) Br. and Sch. Plate XT. is 2 
Synon.: Leskea spruce Bruch (in litt.) 1845. — Spruce, Lond. Jour. Bot. 
180. 1845.— Wilson, Bry. Brit. 330. 1855 (3 ed.). 
flypnum sprucet Bruch (in détt.) 1845.—C. Mueller, Syn. Musc. Frond, 
22415. 1851.—Lesq. & James, Man. Moss. N. Am. 372. 1884. 
Amblystegium sprucei Bruch & Schimper, Bry. Eur. Amblystegium 5, 7. 
7. 1853.—Schimper, Syn. Musc. Eur. 588. 1860 (1st ed.); 705. 1876 (2d. 
ed.).— Milde, Bry. Siles. 322. 1869.— Hartmann, Handb. Skand. Flora 21. 
pe (1oth ed.).— Hobk. Synops. 163. 1873.— Lindberg, Musci Scand. 32. 
1879. — R. du Buysson, Essai analyt. du genre Amblystegium. 1883.— Bou- 
lay, Muse. Fr. 82. 1884. — Mac. & Kindb, Cat. Can. Pl. 6 :217. 1892.— Hus- 
not, Musc. Gall. 356. f/. zo2, 1893.—Dixon & Jameson, Handb. Brit. 
Mosses 441, A/. 55. 1896.—Braithwaite, Brit. Moss Flora. 3:28. ne 89. 1896. 
Platydictya sprucei Berkeley, Handb. Brit. Mosses 145. 
nen Hypnum confervoides Drummond, Musc. ee (Coll. I) 
ica sprucei Macoun, Can. Musc. 315 (Herb. Wis.). 
TyPE in herb, Bruch, Berlin ? 
Gametophyte unisexual, minute, slender, densely cespitose, 
tufts bright green above, not shining, becoming yellow with 
