Plants small to medium-sized, not polytrichoid, gregarious, in loose tufts. Stems simple or sparingly branched by innovation. Leaves various, weakly sheathing at base, ± plane to distinctly channeled or subtubulose, erect when dry and sometimes crisped, erect spreading when moist (in O. falcatum falcate-secund wet or dry), ovate-lanceolate to lanceolate to oblong-elliptic; apex flat or cucullate, acute, obtuse, or apiculate, the margins subentire, denticulate or coarsely serrate, the margins not bordered by linear cells; costa percurrent or short-excurrent, toothed towards apex or with low abaxial lamellae; lamina broad, 1-stratose, the abaxial surface with low projecting teeth, and often with abaxial lamellae; adaxial lamellae confined to the costa, straight or more often transversely undulate, margins entire to sharply serrate, the marginal cells in cross-section not differentiated, smooth. Sexual condition dioicous; perigonia often disproportionately large, the bracts broadly ovate, at times colored and petaloid, overlapping, forming a conspicuous rosette; perichaetial leaves longer and narrower than the vegetative leaves. Seta typically solitary, smooth. Capsule cylindric, usually broadest near the base, terete, often rugose or sometimes with 4 or more indistinct angles or ridges, hypophysis not differentiated, tapering, with stomata at the base; exothecial cells not papillate or pitted; operculum rostrate; peristome teeth 32, pale, subacute to obtuse, compound or sporadically simple. Calyptra sparsely hairy. Spores finely papillose.
|[Greek oligo-, few, and trichos, hair, alluding to calyptra]|