Hypnum sommerfeltii Myrin, Årsberatt. Bot. Arbeten. Upptackter 1832: 328. 1832, based on H. affine Sommerfelt, Suppl. Fl. Lapp., 62. 1826, not Hooker 1822; Campylium hispidulum var. sommerfeltii (Myrin) Lindberg; C. sommerfeltii (Myrin) Lange

Plants green, yellow-green, or yellow-brown. Stems with paraphyllia absent; axillary hair distal cells 1-3, linear or shortly so. Stem leaves sometimes more erect when dry, ± recurved, sometimes slightly homomallous, densely or sparsely inserted, 0.2-0.5 mm wide; base erect to almost spreading; acumen 43-62% leaf length; basal alar cells long- to short-rectangular, distal alar cells quadrate to rectangular, alar region large, reaching from margin 40-50% distance to costa at insertion. Seta 1.2-2.2 cm.

Lowlands, mountains, subalpine, decaying wood, soil, rock; low to high elevations (0-3000 m); Greenland; Alta., N.B., Nfld. and Labr. (Nfld.), N.W.T., Ont., Que., Sask., Yukon; Alaska, Colo., Minn., N.H., N.Y., Pa., S.Dak., Tenn., Vt.; Mexico; West Indies (Guadeloupe, Hispaniola); Central America (Guatemala, Honduras); South America (Bolivia, Colombia, Ecuador, Peru, Venezuela); Eurasia.