Plants 1--5 cm tall, mostly unbranched or rarely with slender sub-apical innovations. Stem leaves 4--10 mm, numerous in rosettes, from 18--55, typically more than 20; margins strongly revolute to above mid leaf, often nearly to apex, apex broadly acute to cuspidate; costa percurrent to short-excurrent into a slender hairpoint in rosette leaves, in cross section with distinct stereid band, reaching dorsal epidermal layer without intervening thin-walled layer of cells; distal and median laminal cells hexagonal, 25--35 × 50--80 µm, (3--4:1), proximal cells longer, to 100 µm, rectangular. Inner perichaetial leaves with costa strong, long-excurrent in denticulate hairpoint. Spores 16--24 µm.

Capsules mature late winter--late fall (Feb.--Nov.). Common on rich soil in forests, along forest edges, on rotten logs, tree bases, soil over rock or rock, often calcareous, sometimes in boggy sites; 0--3000 m, restricted to higher elevations in southern latitudes; Alta, Man., N.B., Nfld., N.S., Ont., Que., Sask.; se Ariz., Ark., Conn., Del., D.C., n Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Pa., R.I., n S.C., S.Dak., Tenn., w Tex., Vt., Va., W.Va., Wis.; Mexico; Eurasia; Asia (India, Japan, mainland southeast Asia).

This is a common and characteristic species of the eastern deciduous forests, occurring as far south as Arkansas and Georgia, with disjunct populations in the mountains of west Texas, New Mexico and southeastern Arizona. Rhodobryum ontariense is not found in Arctic tundra and is rare in the northern boreal forests.