48 American Midland Naturalist Monograph No. 6 



into the narrow acumination much smaller, short-rectangular to rounded, 

 .003-.010 mm in diameter, thick-walled: seta bright yellow, slender, 1-2.5 cm 

 long; capsule about 2 mm long, often slightly curved, narrowly ovoid cylindric, 

 abruptly narrowed below into a slender, curved hypophysis, about as long or 

 slightly longer than the urn and strumose at the base with a goiter-like swell- 

 ing; operculum with a slender beak about two-thirds as long as the urn; 

 annulus large, revoluble peristome dark red, borne on a basal membrane 

 which projects above the mouth of the capsule, the teeth 16, awl-like, more or 

 less irregularly perforate or cleft or entirely divided, striate longitudinally; 

 capsule with a reddish rim of a few rows of small, incrassate, rounded cells, 

 below which the cells become linear and incrassate; spores rough-warty, ,023- 

 .024 mm in diameter, mature in June. 



On clayey soil in open ground, Virginia to Newfoundland and Alaska. 



Cresson, Cambria Co., James and Porter: and Westmoreland County, on recently dis- 

 turbed clay soil around sawmill, altitude 1300 ft., two miles north of Darlington, Chestnut 

 Ridge, May 29, 1949, O.E.J, (figured). 



2. Trematodon longicollis Richard 



Cespitose, light green to brownish-green; stems erect, usually about 5 mm 

 high; leaves abruptly linear-subulate from a concave ovate base, the subulation 

 canaliculate, minutely serrulate at apex; costa scarcely reaching the apex; leaf- 

 cells as in T. ambiguus; pcrichastial leaves quite gradually long-acuminate: seta 

 similar to T. ambiguus; collum twice as long as the urn; urn more strict'y 

 oblong-cylindric; peristome- teeth 16, narrow-subulate, nodosely articulate, 

 usually perforate rather than cleft. Otherwise very similar to T. ambiguus. 



In old fields, etc., on sandy or clayey soil, in Europe, Asia, and in North 

 America, from Massachusetts, Pennsylvania, and Ohio southwards to Florida 

 and Mexico. Not yet reported in our region, but to be expected. 



3. Pleuridium Bridel 



Autoiccus or paroicous, rarely synoicous: weak, green or yellowish-green, 

 cespitose or gregarious: stem with a central strand, radiculose at base, perennial 

 by means of fertile shoots below the apex and by means of sterile flagella; 

 leaves mostly terminal, erect-spreading, sometimes secund, linear-subulate from 

 a broader base, upwards weakly denticulate, sometimes thickly imbricated; 

 costa varying from weak and ending below the apex to very broad and filling 

 the whole acumen, often rough-serrate dorsally; seta mostly very short and 

 erect, rather curved; capsule mostly immersed and oval to ovate-globose, short 

 pointed, sometimes obliquely so, cleistocarpous, without a collum; calyptra 

 cucullate, cleft almost to the apex on one side, covering scarcely half the 

 capsule. 



About 30 species widely distributed, mainly in temperate regions, on soil. 

 Six species occur in North America, at least one in our region. The following 

 key is adapted from Grout's Moss Flora. 



