334 A MANUAL OF MOSSES 



membrane about one-fourth the height of the teeth ; lid high- 

 conic, usually acutely apiculate ; spores papillose, brownish, 

 medium- to thick-walled, .G12-.016 mm., mature in autumn. 

 Very closely related to the following species, which it ap- 

 parently replaces to the west and northwest of our region. 



On roots and bases of trees and on old logs, in woods 

 from our region northwestward to Minnesota and Ontario. 

 Uncommon in our region. 



Allegheny : Fern Hollow, Pittsburgh, on old logs in 



ravine, January 21, 1906 (Figured), and 

 March 8, 1908. O. E. J. 



McKean : Bradford. D. A. B. (Porter's Catalogue). 



2. Brachythecium acuminatum ( Hedwig) Kindberg. 

 (Leskca acuminata Hedwig; Hypnnm acuminatum Beauvois). 



(Plate XLIX) 



Widely and somewhat densely cespitose, dark to yellow- 

 ish-green, glossy : stems slender, prostrate, up to 5 to 8 cm. 

 long, bearing rhizoids, at least near the perichaetia, rather dis- 

 tantly and unequally branched, the branches two-ranked, 

 plumose to sub-julaceous, acute, not usually more than 1 cm. 

 long ; stem-leaves close, erect-spreading, lance-ovate to ovate, 

 about 1-1.5 mm. long, acuminate, concave, with the borders 

 reflexed below, the upper half serrulate, the leaf non-plicate or 

 but slightly plicate ; narrowed and somewhat decurrent at the 

 base ; costa usually reaching beyond the middle of the leaf ; 

 branch-leaves similar to the stem-leaves but relatively nar- 

 rower and smaller ; median leaf-cells linear-flexuose, about 

 8-12:1, medium-walled, prosenchymatous with rounded ends, 

 apical cells a little shorter, the basal sub-quadrate or sub- 

 rectangular, the alar numerous and sub-quadrate to quadrate, 

 rather thin-walled and sub-inflated : seta erect, castaneous, 

 flexuous, about 1-1.5 cm. long; capsule castaneous, erect, the 

 urn 1.5-3 mm. long, sometimes slightly curved, cylindric, 

 about 3.5-4.5:1, tapering at base; lid high-conic, acute to 

 apiculate ; exothecial cells densely yellowish-incrassate, small, 

 rounded but varying to quite irregular in size and shape but 

 with rounded corners ; peristome-teeth narrow, castaneous, 

 numerously trabeculate, hyaline and papillose above, dorsally 

 cross-striolate below, the lamellae distinct, teeth confluent at 

 base ; segments about as long as the teeth, narrow, carinately 

 split, cilia rudimentary or none, the basal membrane only about 

 one-fourth as high as the teeth ; annulus none ; spores castane- 

 ous, papillose, medium-walled, about .014-.018 mm., mature in 

 late fall or in winter. 



On earth, woods-humus, roots and bases of trees, stones, 

 and very often on rotten logs, forming wide mats, in woods 



