Plagiopus Brid., Bryol. Univ. 1: 596. 1826.
[Greek plagios, oblique, referrring to curved seta + pus, foot]
D. Griffin, III
Plants in dense, dull olive green to brownish tufts, radiculose below. Stems erect to ascending, forked, triangular in cross section with a cortical layer of lax, thin-walled, hyaline cells; central strand present. Leaves laxly erect or erect spreading and somewhat curved when dry, erect spreading when moist, narrowly lanceolate, acuminate, keeled above, not sheathing; margins revolute in distal half, occasionally in distal 3/4, often 2-stratose and doubly serrate distally; costa percurrent to short excurrent, prominent, rough on back; distal laminal cells subquadrate or short-rectangular, thick-walled and faintly striated, basal cells longer and thinner walled, especially toward costa. Specialized asexual reproduction not known. Sexual condition synoicous; perichaetial leaves scarcely distinct. Seta solitary, elongate, erect or flexuose, smooth. Capsule suberect, subglobose, furrowed when dry, small mouthed; annulus lacking; operculum small, low conic or convex; peristome double, teeth reddish brown, smooth or minutely papillose, lanceolate with intermediate thickenings on internal dorsal plates not paired with cross walls on external dorsal plates; endostome yellowish to hyaline, basal membrane well developed, segments broad, cilia short, rudimentary or lacking. Spores ellipsoid, coarsely papillose.
Species 1--2 (1 in the flora). Worldwide, except Antarctica.
Plagiopus is distinguished by its triangular stems, striated leaf cells, and leaves appearing papillose in cross section.
Crum, H.A. and L.E. Anderson. 1981. Mosses of Eastern North America. Vol. 1, p. 635, New York. Flowers, S. 1935. Plagiopus. In: A.J. Grout, ed., 1935. Moss Flora of North America 2(3): 157. Newfane, Vermont. Ireland, R.R. 1982. Moss Flora of the Maritime Provinces. National Museums of Canada, Natl. Mus. Nat. Sciences, Publs. in Bot. 13. Ottawa. Lawton, E. 1971. Moss Flora of the Pacific Northwest. Nichinan.