1. Scorpidium revolvens (Swartz) Rubers in A. Touw and W. V. Rubers, Nederl. Bladmoss. 380. 1989.
Hypnum revolvens Swartz ex Anonymo, Monthly Rev. 34: 538. 1801; Drepanocladus revolvens (Swartz ex Anonymo) Warnstorf; D. revolvens var. miquelonensis (Renauld & Cardot) Grout; Limprichtia revolvens (Swartz ex Anonymo) Loeske
Plants medium-sized to large (sometimes when submerged), not turgid, green, red, purplish red, dark brownish red, or blackish red. Stems sparsely and irregularly branched or sometimes ± pinnate, shoot apices not hooked; hyalodermis well developed, complete. Stem leaves ovate or ovate-lanceolate, gradually or sometimes abruptly narrowed to apex, ± suddenly curved distally, concave, 0.5-1 mm wide; apex acuminate or long-acuminate, sometimes apiculate; costa single, ending beyond mid leaf; alar cells 2-10; medial laminal cells (shorter 1/2 of leaf) 61-140(-179) µm, cell ends short or long fusiform-narrowed, rarely rounded to almost square. Sexual condition autoicous. Capsule with exostome external surface more than 40-50% cross striolate basally.
Mountains, intermediately mineral-rich and often spring-influenced fens, small periodically water-filled depressions, shores, submerged; low to high elevations (0-3100 m); Greenland; St. Pierre and Miquelon; Alta., B.C., Man., Nfld. and Labr., N.W.T., Nunavut, Ont., Que., Sask., Yukon; Alaska, Colo., Idaho, Mich., Minn., Mont., Ohio, Vt., Wis., Wyo.; South America; Eurasia; s Africa; Pacific Islands (New Zealand, Papua New Guinea); Antarctica.
Scorpidium revolvens often has been confused with 2. S. cossonii; the differences between these species are discussed under the latter.