228 A MANUAL OF MOSSES 



tome inserted on the mouth, double; teeth lance-linear, yel- 

 low, broadly bordered, non-striate, trabeculss thickened ; basal 

 membrane not prominent, segments narrowly linear, carinate- 

 ly cleft, cilia none; spores .012-018 mm., lid conic, shortly 

 and obliquely rostrate. 



A widely distributed genus of about 11 species : one species 

 in North America. 



1. Platygyrium repens [Bridel] Bryologia Europaea. 



(Pterogoniuin repens Schwaegrichen ; Anomodon repens Fuern- 

 rohr ; Cylindrothecium repens DeXotaris : Entodon repens 

 Grout). 



(Plate XXXIII) 



Densely but thinly matted, bright to dark green, pinnately 

 branching: leaves ecostate, crowded, erect-spreading when 

 moist, imbricate when dry, concave, subscarious, lustrous, 

 ovate to long-lanceolate, about 0.7-0.9 mm. long, acuminate, 

 the margin entire and recurved below;. leaf-cells all medium- 

 walled, at apex rhomboidal, the median linear-rhomboidal 

 prosenchymatous, about 6-9:1, the alar distinct, quadrate and 

 relatively large, extending up the margin; inner perichsetial 

 leaves about twice as long as the branch-leaves, ecostate, 

 more acuminate : seta erect, 10-15 mm. long, smooth, lustrous, 

 dark-castaneous, sinistrorse; urn of capsule about 1.0-1.2 mm. 

 long;^, erect, symmetric, oblong-cylindric, castaneous, not nar- 

 rowed below the mouth when dry; operculum about two-fifths 

 the length of the urn, slenderly and obliquely but bluntly 

 rostrate ; annulus persistent, large, 2-3-seriate, and appearing 

 like modified upper exothecial cells ; peristome-teeth rather 

 deepl)'^ inserted, linear-lanceolate, light yellowish-brown, 

 strongly about 15-18 trabeculate, widely hyaline-bordered, 

 papillose below in irregular and often radiating lines, but not 

 cross-striate below as in most hypnaceous peristomes, lamellae 

 and divisural line rather indistinct ; segments about two-thirds 

 as long as teeth, linear, narrow, arising from a very low basal 

 membrane, more or less carinately cleft ; cilia none ; exothecial 

 cells quadrate to irregular or oblong-hexagonal, yellowish; 

 spores about .014-.018 mm., yellowish, minutely rougliened, 

 mediurh-walled, mature in autumn ; gemmae often abundant in 

 the axils of the upper leaves. 



On bark at base of trees, on decaying logs, stumps, and 

 in woods; widely distributed in the Northern Hemisphere; in 

 North America from New Brunswick to the Pacific and south 

 to the Gulf of Mexico. Very common in our region. 



Allegheny : More than 40 pockets from various locali- 



ties in the county, 1905-1911, mostly O. 

 E. J. and G. K. J. ; on rotten log in oak 



