Jennings: Manual of Mosses — 5. Pottiaceae 89 



mostly with a strong excurrent costa; upper leaf-cells quadrate to hexagonal, 

 warty-papillose on both sides, rarely smooth; basal leaf-cells rectangular and 

 hyaline: seta very short, sometimes curved; capsule immersed or slightly 

 emergent, sometimes two in a perichaetium, mostly globose and obtusely 

 apiculate, with no indication of an operculum; calyptra cucullate or rarely 

 mitrate, small, conic. 



A widely distributed genus of 15 species, on soil; 5 occurring in North 

 America, one in our range. 



1. Phascum cuspidaTum [Schreber] Hedwig 

 (P. acaulon Linnaeus) 



Cespitose, deep green: stems short, 1-2 mm high, simple or forked; leaves 

 crowded, erect, the comal longest, oblong-lanceolate, acuminate, more or less 

 carinate, entire, revolute towards middle; costa excurrent; basal cells lax, hy- 

 aline, the upper rectangular to hexagonal, .015-.030 mm, finely dorsally papil- 

 lose: seta short, straight or curved; capsule globose, sometimes two or three 

 on the same plant, immersed or rarely emergent, obtusely apiculate, about 1 

 mm long, cleistocarpous; calyptra cucullate, conic, covering only the upper 

 portion of the capsule; spores large, .028-.035 mm, yellowish-pellucid, finely 

 roughened, mature in spring: autoicous or paroicous, antheridia clustered in 

 the axils of the upper leaves. 



On soil in old fields, pastures, etc., usually preferring a sandy soil, in 

 Europe, Asia, Algeria, South America, and from Ontario to Virginia and 

 west to Arizona. 



Rare in our region. Beaver Co.: T. P. James. (Porter's Catalogue). 



1 1 . Pottia Ehrhart, Fuernrohr 



Autoicous or paroicous, rarely synoicous or dioicous: small, gregarious to 

 cespitose, green to brownish or whitish: stem with central strand above, often 

 simple, radiculose at base, leafy; leaves tufted above, spreading to imbricate, 

 carinate to deeply concave, oblong to elongate-lanceolate, or spatulate, acu- 

 minate to piliferous, rarely obtuse, margin revolute or plane; costa without 

 lamellae, complete to excurrent, rarely incomplete; lower leaf-cells elongate, 

 pellucid, smooth, the upper rounded-quadrate or rounded-hexagonal, mostly 

 papillose on both sides: seta mostly long and straight; capsule exserted or 

 rarely immersed, erect, symmetric, short-necked; annulus none or deciduous 

 or remaining attached; peristome often none or rudimentary, when present of 

 16 perforate or upwards 2-3-cleft teeth upon a basal membrane, articulate; 

 operculum mainly obliquely rostrate, rarely conic-obtuse, sometimes not de- 

 ciduous; calyptra cucullate, papillose or smooth, usually falling away with the 

 operculum; spores large, variously papillose or pitted. 



A genus of about 50 species widely distributed, on soil or soil-covered 

 rocks, mainly in the temperate zones; 12 species in North America, 1 species 

 in our region. 



