188 
Type locality European. 
Subaquatic, on moist rocks in woods and in brooks, especi- 
ally in mountain regions. Northeastern United States and Can- 
ada; west to Minnesota; British Columbia (Macoun); south to 
North Carolina. ALT ; 
ILLustRATIONS.—Br. & Sch. |. c. ; Hedw. l. c. ; Wils. Bryol. 
Brit. J 25 ; Husnot, Musc. Gall. A. 94. 
ExsiccATr.—Sull. Musc. Allegh. 40; Sull. & Lesq. Musc. 
Bor. Am. (Ed. 1) 332, (Ed. 2) 496 and 498 ; Austin, Musc. Appal. 
325, 326, 327 ; Macoun, Can. Musc. 289; Ren. & Card. Musc. 
Am. Sept. Exsic. 110. 
18a. B. PLUMOSUM HOMOMALLUM Br. & Sch.l c. Branches 
curved at apex, leaves falcate-secund, smaller. With the ordinary 
form. | 
ExsiccATr.—Sull. Musc. Allegh. 41 (Hypnum pseudo-plumo- 
sum ; Sull.& Lesq. Musc. Bor. Am. (Ed. 1) 332^, (Ed. 2) 497. 
Distinguished from most of the species by having the seta 
smooth below and rough above ; from B. campestre by having the 
leaves shorter, more abruptly pointed, nearly entire and not 
plicate; from B. populeum by the shorter costa, which does not 
extend into the apex; all the accessible descriptions speak of the 
perichaetial leaves as ecostate, but the perichaetial leaves of Lim- 
pricht's Bryol. Sil. 242 and Husnot's Musc. Gall. 277a were very 
conspicuously costate and such was the case in all the American 
specimens examined. Specimens of B. rutabuliforme from the 
type collection have the seta nearly smooth below instead of very 
rough and are certainly referable to B. plumosum. 
19. BRACHYTHECIUM POPULEUM (Hedw.) Br. & Sch. Bryol. Eur. 
fasc. 52-54, pl. 535 and 536. 1853. 
Hypnum populeum Hedw. Sp. Musc. 270. pl. 70. f. 1-6. 
1801. | . 
Hypnum Stereodon Laureri Funck ; Brid. Bryol. Univ. 2: 595. 
1827. (Fide Limpricht). 
Hypnum saxicola Voit ; Sturm, Deutschl. Fl.2: fasc. 12. 1812. 
Brachythecium nanopes C. Muell. & Kindb. Macoun, Cat. Can. 
PL 6-201. 1892. 
