2 
with spreading points, oblong-lanceolate, abruptly narrowed to a 
long filiform acumination, nearly entire or somewhat serrulate 
above, costa thin or wanting. Sporophyte 1.5—2.5 cm. high; seta 
red-brown, smooth ; capsule red-brown, oblong-cylindric, suberect, 
slightly arcuate, somewhat contracted below the mouth when dry, 
the neck gradually narrowed to the seta, 2.5—3.5 mm. long, about 
4: I; operculum long conic to conic-rostrate ; annulus none; 
teeth of peristome light red-brown, rather abruptly narrowed to a 
slender hyaline point; segments from a broad basal membrane, 
nearly as long as the teeth; cilia two, strongly nodose or ap- 
pendiculate ; spores finely papillose-roughened, about 15, ma- 
turing in autumn or early winter. 
Type locality, Penn. (Ludwig). 
On earth rocks, and roots of trees in woods. Northeastern 
United States and eastern Canada; west to Minnesota, Kansas 
and Nebraska ; Colorado (Brandegee); south to North Carolina 
and Tennessee; Missouri (Bush). Apparently common. 
ExsiccATI.—As H. laetum Drumm. Musc. Am. (S. States), 
122; Sull & Lesq. Musc. Bor. Am. (Ed. 1) 329, (Ed. 2) 488, 
489, 490; Austin Musc. Appal. 309; Macoun, Can. Musc. 281, 
566 (B. spurio-acuminatum); Ren. & Card. Musc. Am. Sept. 
Exsic. 104, (B. diventrosum). 
ILLUSTRATIONS.— Br. & Sch. l. c.; Sull. Icon. Musc. AJ. 775; 
Husnot, Musc. Gall. 4. 93; Rab. Krypt. Fl. 4: f. 574. 
Type specimens of both B. oxycladon and B. laetum have been 
examined. The branch leaves of the former are less serrate than 
those of the latter but the acumination and serration of the leaves 
varies so much even on the same plant, that these characters alone 
cannot be used even to separate varieties. The species is exceed- 
ingly variable and difficult to separate from its allies, especially B. 
salebrosum ; the difficulty is increased by the fact that the species 
is very imperfectly dioicous. 
Examination has been made of authentic specimens of B. /ae- 
tum var. fallax R. & C. (Bot. Centralbl. 44: 422. 1890), B. lae- 
tum var. pseudo-acuminatum R. & C. 1. c.; B. laetum Roelli R. 
& C. I c., from type locality and from Herb. Cardot. The va- 
riety fallax seems to be nothing more than a local form with nar- 
