OF WESTERN PENNSYLVANIA 343 



rough, castaneous, flattened and twisted when dry ; capsule 

 about 2-2.5 mm. long, 2-3 ;1, turgid-oblong, dorsally gibbous 

 to sub-arcuate, castaneous, inclined to horizontally spreading; 

 exothecial cells small and rounded-quadrate at rim, oblong- 

 rectangular below, all densely incrassate ; peristome-teeth 

 slender, .castaneous and confluent at base, apically hyaline and 

 papillose, dorsally cross-striolate, closely trabeculate and 

 lamellate; segments nearly as long as the teeth, slender, cari- 

 nateh' split between the nodes, yellowish, the basal membrane 

 one-third to two-fifths as high ; cilia 2 or 3, nodose, hyaline, 

 somewhat shorter than the segments ; lid conic-acuminate, 

 about 0.5-0.8 mm. long ; annulus large ; spores mature in win- 

 ter, faintly roughened, medium-walled, brownish, .013-016 

 mm. in diameter. 



On earth, rocks, bases of trees, rotting wood, etc., in rather 

 dry woods, often on knolls ; Europe, Asia, and from Arctic 

 America south to New Jersey and Pennsylvania and also in 

 the Pacific States. Thus far reported but once in our region. 



McKean : Langmade, near Bradford, April 25, 1898. 



D. A. B. (Figured). 



13. Brachythecium populeum (Hedwig) Bryologia Europaea. 



(Hypnum populeum Hedwig). 



Slender, densely cespitose in small yellowish green tufts, 

 lustrous: stems procumbent, branched with numerous, more 

 or less pinnately-arranged, erect or curved-ascending branches ; 

 leaves of stem and branches similar except that the branch- 

 leaves are narrower and lanceolate ; stem-leaves rather closely 

 imbricated, erect to erect-spreading when dry, ovate-lanceolate, 

 serrate to nearly entire, slenderly and gradually acuminate, 

 non-striate, shortly decurrent; costa strong and nearly reach- 

 ing the apex ; median leaf-cells about 5-8:1, sometimes relative- 

 ly longer, the basal more or less rectangular, the alar numerous, 

 often yellowish but rather opaque ; seta rough except towards 

 the base, where nearly smooth, dark brown ; annulus persistent, 

 simple, narrow ; capsule cernuous, turgid-ovate to oval, mostly 

 dorsally gibbous, glossy, constricted at the mouth when dry; 

 lid short-acuminate ; peristome normal, cilia short, usually 1 or 

 2 and unequal, appendiculate ; spores mature in winter; au- 

 toicoils. 



On roots of trees, stones, sometimes on bases of trees, in 

 shady woods, said to be somewhat partial to pine woods; 

 Europe, northern Africa, and from Nova Scotia to North Caro- 

 lina and in British Columbia. Rare in our region. 



McKean : "B. populeum rufescens." Bradford l\ A. 



B. (Porter's Catalogue). 



