Plants in dull, dark green to yellow-brown, rather rigid mats; pseudoparaphyllia none. Leaves erect-appressed or rarely subsecund when dry, erect-spreading when moist, 0.15--0.3 mm, not much narrowed to the insertion, entire or nearly so; distal cells 2--3 (rarely 4):1, oblong-rhombic; alar cells subquadrate in small, inconspicuous groups of 3--6 cells, rarely more, at the basal margins. Specialized asexual reproduction absent. Sexual condition autoicous. Perichaetial leaves entire or obscurely serrulate above. Seta 6--8 mm. Capsule inclined to horizontal and asymmetric or rarely suberect, 0.8-- 1.2 mm, shortly oblong-cylindric, contracted below the mouth when dry; annulus of 2 layers of cells; operculum convex-conic, stoutly apiculate; stomata at base of the capsule; peristome teeth yellow-brown; cilia of endostome in 2's and 3's. Spores 11--13 µm.

Moist, shaded limestone rocks, especially in stream valleys; low to moderate elevations; Nfld., N.S., Labrador, Ont., Que., Yukon; Alaska, Ala., Conn., Ill., Ind., Iowa, Kans., Md., Mich., Minn., Mo., N.J., N.Y., Ohio, Pa., S.Dak., Tenn., Vt., Va., Wis.; Europe; Asia (Caucasus).

Diagnostic features of this species include the entire or obscurely serrulate leaf margins and short cells, as well as its rupestral habitat.