292 American Midland Naturalist Monograph No. 6 



yellowish-incrassate; peristome-teeth slender, confluent at base, closely trabecu- 

 latc and lamellate, dorsally cross-striolate and brownish below, hyaline and 

 papillose above, rather prominently margined; segments about as long as the 

 teeth, finely papillose, carinately split and usually gaping; cilia a little shorter, 

 hyaline, nodose, 1 to 3 in number; basal membrane about one-third as high 

 as the teeth; spores mature in late fall or winter, about .015-.020 mm, the walls 

 medium-incrassate, brownish, and somewhat papillose: autoicous. 



On earth, stones, roots and bases of trees, rotten wood, etc., in moist, shady 

 woods; said to be especially common in pine or hemlock woods; Europe, Asia, 

 northern Africa, and from eastern Canada southward to North Carolina and 

 Missouri. 



Common in our region. Now known from the following counties: Allegheny, Bedford, 

 Butler, Crawford, Clinton, Elk (Porter), Erie, Greene, Indiana, Lawrence, McKean, Som- 

 erset, Washington, and Westmoreland. Specimen figured: Douthett, Allegheny Co., 

 April 26, 1908. O.E.J. 



4. Brachythecium flexicaule Renauld and Cardot 



Plate LV 



Widely cespitose, yellowish-green: stems usually at least 3-6 cm long, 

 creeping, irregularly pinnate; leaves plicate, erect-spreading, the stem-leaves 

 lanceolate, about 1.8-2.5x0.6-0.9 mm; branch-leaves narrower, up to 2.4 x 0.5- 

 0.7 mm, gradually slenderly acuminate from a deeply concave, somewhat 

 decurrent plicate base with often narrowly reflexed basal margins, the margins 

 serrulate above; costa extending to above the middle of the leaf; median leaf- 

 cells linear-fusiform, prosenchymatous, flexuous, about 8-15:1, rather incras- 

 sate, the apical shorter, the basal rather abruptly shorter and wider with two 

 to four rows of large oblong to rounded-quadrate cells across the whole median 

 base, the alar cells sub-quadrate, rather incrassate, numerous, the wings decur- 

 rent; perichaetial leaves up to 3 mm long with slender flexuous acuminations, 

 partly sheathing, erostate or nearly so: seta smooth, castaneous, usually sinis- 

 trorse, 1.5-2.5 cm long; capsule about 3-4:1, oblong-cylindric, inclined to 

 nearly horizontal, dorsally gibbous, sub-arcuate, pale-castaneous, slightly nar- 

 rowed below the rim when dry, the urn from 2-4 mm long; lid conic-acumi- 

 nate, about 1-3 mm long; exothecial cells small and rounded at the rim, below 

 larger and oblong to linear-oblong, all sharply yellowish-incrassate; annulus 

 indistinct; peristome-teeth confluent at base, castaneous and dorsally cross- 

 striolate below, closely trabeculate and lamellate, margined, hyaline towards 

 apex; segments very slender, about as long as teeth, carinately cleft and gaping 

 in median portion, yellowish, papillose, basal membrane one-fourth to one- 

 third as high, the cilia somewhat shorter than the segments, filiform, nodose, 

 hyaline-papillose; spores rather incrassate, smoothish, brown-walled, .013-. 016 

 mm. According to Grout this is probably B. salebrosum variety densum Bry- 

 ologia Europaea. In most characters it is quite similar to typical salebrosum 

 but differs in having narrow leaves with evenly narrowed and very slender 

 acuminations. 



