Plants small to medium-sized, in loose or dense tufts, mats or compact sods, fragile, dull green, yellowish to dark green distally, black, brown or tan proximally with prominent shining costae. Stems erect, often branched, in transverse section with hyalodermis, somewhat weak sclerodermis, central strand absent or present, rhizoids dense or few at the base, occasionally tomentose; axillary hairs long, 1-seriate, of 10-20 cells, hyaline. Stem leaves cirrhate-crispate to incurved when dry, spreading to recurved when moist, elongate-oblong to linear-lanceolate or linear-subulate, widest at or near the base; base hyaline, oblong, erect; margins plane to incurved distally, generally entire and minutely crenulate by projecting papillae, but often slightly or irregularly scalloped by indentations at points of laminal weakness, occasionally somewhat to strongly undulate, rarely with a border of elongate, clear, smooth cells in one series beyond midleaf, gradually tapering distally or more or less abruptly narrowed; apex acute or obtuse, cucullate or concave, with an apiculus, mucro or short subula; costa strong, percurrent to short-excurrent, adaxial and abaxial epidermal cells often present, often interrupted, adaxial and abaxial stereid bands and 1 layer of median guide cells present, hydroid strand occasionally present; proximal cells enlarged, laxly long-rectangular, thin-walled, hyaline, occasionally brown and rather thick-walled, smooth, abruptly differentiated from the green cells distally or gradual in transition, limit of the proximal region usually appears as a V, sometimes a U, often extending distally up each leaf margin as a short or elongated border; distal laminal cells medially and distally rounded-hexagonal, chlorophyllose, frequently obscured by numerous, dense, C-shaped papillae on both surfaces. Specialized asexual reproduction at the stem apex occasional, by deciduous or fragile propaguloid leaf tips, or by deterioration of fragile leaves along zones of laminal weakness. Sexual condition dioicous, occasionally autoicous; perigonia terminal, short-foliose to gemmate or as stalked buds in leaf axils of perichaetiate plants; perichaetia terminal, leaves not or little differentiated, or distinct and long-setaceous. Seta 1(-2) per perichaetium, yellow or reddish proximally with age, to 3 cm, erect, smooth. Capsule erect and symmetric or slightly inclined, yellow to reddish brown, darker red or brown at mouth, elliptic to cylindric, more or less wrinkled-plicate when dry and empty; annulus sometimes present, of 1-4 rows of vesiculose cells, persistent; operculum conic or long-rostrate, half as long as the urn or longer, straight or inclined; peristome orange-red, single, with a low basal membrane, of 32 filiform rami joined at the base into 16 pairs, twisted counterclockwise or merely obliquely inclined, branched-spiculose, rarely nearly smooth. Calyptra cucullate, smooth. Spores 8-12(-20) µm, yellowish brown, moderately coarsely to finely papillose to nearly smooth.
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