Cells of the mid-limb lamina (6–)7–10(–12) µm wide (mean 8.5 µm); cells of distal part of leaf sheath non-papillose on abaxial surface (rarely papillose in non-North American specimens). Calyptra: not persistent on seta.
Often with sporophytes. Most often in mesic, calcareous, open or well-vegetated Arctic-montane sites, or in nutrient-rich sites such as the bases of cliffs or around large boulders. low to high elevations (0-3000 m). Greenland, Alta., B.C., Man., N.W.T., Nunavut, Ont., Que., Sask., Yukon, Alaska, Ariz., Colo., Idaho, Mont., Nev., N.Mex., Utah, Wyo., Mexico, Eurasia (Caucasus, China, n, c Europe, Greece, India, Japan), n Africa (Algeria), Atlantic Islands (Iceland), Pacific Islands (Hawaii). Discussion.