266 American Midland Naturalist Monograph No. 6 



or sub-denticulate at the apex, the leaves rather shortly and broadly acuminate, 

 the tip flat and widely acute to somewhat obtuse, the decurrent auricles are 

 made up of large, oblong, inflated, thin-walled, and hyaline cells bordered 

 above by about two series of smaller, quadrate, usually brownish-pellucid, 

 thicker-walled cells, these latter grading quickly into linear-vermicular median 

 cells about 12-20:1, the apical cells oblong-rectangular or obliquely more or 

 less rhomboidal; costa very short, and double or none; branch-leaves similar; 

 perichaetial leaves sheathing, the inner lanceolate to lance-linear, up to 6 or 7 

 mm long, plicate, entire, acuminate; seta about 2.5-3 cm long, dextrorse, lus- 

 trous, castaneous; capsule about 2-2.5 mm long, about 4-5:1, oblong-cylindric, 

 erect at base but arcuate so that the lid usually points more or less horizon- 

 tally, when dry plicate but scarcely narrowed below the mouth; annulus large, 

 revoluble; lid conic, apiculate, scarcely longer than wide; peristome hypnoid. 

 the teeth lance-linear, dorsally cross-striolate, yellowish-pellucid below, hyaline 

 and papillose above, the divisural and dorsal lamellae prominent, the trabeculae 

 .<:trong and numerous; segments rising from a basal membrane about two-fifths 

 the height of the teeth, the segments about as long as teeth, narrow, somewhat 

 carinately split; cilia 1-3, shorter, nodose, hyaline-papillose, often joined to- 

 gether above; spores smoothish, yellowish, moderately incrassate, about .014- 

 .018 mm, mature in late spring or early summer. 



On the ground in woods and wet, grassy places in swamps, around springs, 

 etc.; Europe, Asia, and from Arctic America to the northern United States 

 and south, in the East, to Florida. 



Now known from 13 counties in western Pennsylvania and probably occurs in all. 

 Specimen figured: Kittanning, Armstrong Co., May 28, 1907. O.E.J. 



8. Stereodon pratensis (Koch) Wamstorf 



(Hypnum pratense Koch; Isopterygium pretense Lindberg) 

 Plate LXX 



Softly and flatly cespitose, bright green, complanately flattened: stems 

 prostrate to sub-erect, non-radiculose, irregularly sub-pinnate, branchlets rather 

 sparse; leaves sub-secund on the larger branches and on the stems, plane to 

 somewhat concave, entire; costa double and very faint and short or none; 

 median leaf-cells narrowly rhomboid-vermicular, the alar rather gradually 

 enlarged, fewer, less enlarged and less difl^erentiated than in S. Patientiae; peri- 

 chaetial leaves plicate, the inner long-lanceolate and shortly acuminate: pedicel 

 long, twisted in two directions; capsule non-plicate, oblong to turgid-ovate, 

 cemuous, arcuate when dry; lid convex-conic; annulus 3seriate; peristome 

 normally hypnoid, the cilia 3, about as long as the segments; spores mature in 

 spring. The capsules are rarely produced. 



Specimens sometimes show an abruptly enlarged group of alar cells typical 

 of S. Patientiae in the larger stem-leaves, while less vigorous leaves are of the 

 S. pratensis type, as in the Linn & Simonton specimen, see figure, Plate LXX. 



In open swamps and marshy meadows, Eurasia, and from Pennsylvania 

 and New Jersey to Arctic America. Varieties of it range farther south. 



