Plants soft in appearance, 1--3 mm wide measured across leafy stem, to 12 cm long. Stems irregularly branched to loosely 1-pinnate, not frondose or bushy, innovations inconspicuous; branches turgid. Stem leaves loosely imbricate, becoming more tightly imbricate toward stem tips, erect to erect-spreading, ovate to elliptic-ovate, somewhat concave, 1.5--2.5 × 1.0--1.4 mm; margins serrate distally, serrulate to nearly entire toward base; abruptly narrowed to apex; costa single; median cells 30--60 × 5--7 µm. Branch leaves imbricate, ovate-lanceolate to lanceolate, 1.3--2.0 × 0.4--0.9 mm; costa single. Seta 10--30 mm. Capsule ovoid, 1.3--1.8 mm.

Soil, humus, old logs, and rock in moist forests, rarely fens and tundra, often along streams or besides waterfalls, perhaps more common in calcareous areas; 0--3000 m; Alta., B.C., N.B., Nfld., N.W.T., N.S., Ont., Que., Yukon; Alaska, Colo., Maine, Mich., Minn., N.H., N.Y., Vt., Wash., Wis.; Eurasia.