146 American Midland Naturalist Monograph No. 6 



and stem covered with a reddish-brown tomentum; leaves oblong to lanceolate, 

 about 4 mm. long, minutely denticulate towards the apex, carinate, rather cris- 

 pate when dry; costa strong, ending just below apex; upper cells small, round 

 incrassate, unipapillate, basal cells elongate-rectangular or hexagonal, thin- 

 walled: seta erect, tortuous, in ours about 3 cm long, upper part dextrorse, 

 lower part sinistrorse; capsule sub-cylindrical, 4-5 mm long, when dry strongly 

 sulcate, arcuate, constricted below mouth; annulus high, colored at the base; 

 teeth lance-Iinear, subulate-acuminate, yellowish, trabeculae sometimes united 

 by oblique walls, divisural zigzags; segments delicate, slightly shorter, hyaline, 

 cilia about 3, equally long, weakly articulate; spores small, smooth, .008-. 012 

 mm; mature in early summer; operculum long-conic, straight or sometimes 

 somewhat recurved. 



Cosmopolitan. In swampy woods and bogs. In North America from the 

 Arctic regions south over most of the United States. 



Rather common in the northern part of our region. Known from the folio ving coun- 

 ties: Allegheny, Armstrong, Beaver, Butler, Cameron, Centre, Clarion, Clearfield, Clinton, 

 Crawford, Erie, Fayette, Greene, Lawrence, McKean, Mercer, Somerset, Washington, and 

 Westmoreland. Specimen figured: Presque Isle, Erie Co., May 8-9, 1906. O.E.J. 



2a. AuLACOMNlUM PALUSTRE var. IMBRICATUM Bryologia Europaea 

 Leaves more ovate than lanceolate; imbricated when dry, not crispate or 

 contorted. 



From lower Canada down into eastern United States. 



Family 17. MeesiacEAE 



Synoicous, autoicous, dioicous, or polycoicous: robust to slender, cespitose: 

 stem with a central strand, elongate, leaves 3-8 seriate, moderately close, mostly 

 from an erect base erect-spreading to recurved-squarrose, lance-ovate to lance- 

 acuminate, non-bordered, sometimes toothed at the apex; costa strong, without 

 guides, mostly incomplete; cells mostly parenchymatous and smooth, upper 

 firm-walled, rectangular to rounded 4-6-sided, the basal often thin-walled, 

 elongate-rectangular and hyaline: seta mostly long and slender, erect, tortuous; 

 capsule erect, from a long collum elongate arcuate-pyriform, the mouth small 

 and oblique, never constricted below the mouth; annulus small-celled, 1-2-seri- 

 ate, loosening itself here and there, rarely persisting; teeth mostly much shorter 

 than the segments, truncate, more or less completely confluent, with straight 

 divisural and thin rectangular dorsal plates, the inner layer with low lamellae; 

 inner peristome with a carinate basal membrane united to the teeth; segments 

 narrowly linear, alternating with the teeth, cilia rudimentary or none; spores 

 .032-. 056 mm, mostly finely granulate; operculum small, conic, obtuse; calyptra 

 small, cucullate, smooth, fugacious. 



A small family (3 genera) of mostly bog mosses of the cooler parts of 

 the northern hemisphere. One genus represented in our range. 



1. Meesia Hedwig 



Characters mainly as for the family; the tufts green to yellowish-green, 

 inside brown to blackish: leaves more or less decurrent, acute or obtuse, mostly 



