Plants moderate-sized to robust, weak-stemmed; pale brown to chestnut brown; capitulum flat-topped and generally 5-radiate, branches straight to somewhat curved, terminal bud often visible. Stems pale green to brown, superficial cortex of 2 layers of thin-walled and well differentiated cells. Stem leaves triangular, ovate-triangular to triangular-lingulate, 1--1.3 mm; appressed to spreading; apex obtuse, hyaline cells usually fibrillose near apex. Branches straight to somewhat curved, leaves moderately elongate at distal end. Branch fascicles with 2 spreading and 1--2 pendent branches. Branch stems green, cortex enlarged with conspicuous retort cells. Branch leaves ovate-lanceolate; usually more than 2 mm; straight; weakly undulate and slightly recurved when dry, margins entire; hyaline cells on convex surface with numerous small free pores in proximal 2/3 of leaf and in apical region with numerous pseudopores along commissures, on concave surface with numerous round free pores; cells relatively long and narrow in basal region, much longer than in mid-region; chlorophyllous cells triangular in transverse section and well-enclosed on concave surface. Sexual condition dioicous. Spores 29--33 µm; both surfaces very smooth; proximal laesura long, more than 0.6 spore radius.

Predominantly in wet carpets in poor to medium fen habitats, mostly in mire-wide vegetation; Alta., B.C., Nfld., N.W.T., Ont., Que., Sask., Yukon; Alaska; Eurasia.

Sporophytes are uncommon. See discussion of S. annulatum.