Capsule with peristome present, twisted, to 1300 µm; operculum broadly conic, cells twisted.

Capsules mature spring-summer. Soil, calcareous rock, granite outcrop, schist, sandstone; moderate to high elevations (600-2300 m); Alta., B.C., Nunavut; Alaska, Ariz., Calif., Colo., Idaho, Ill., Mont., Nev., N.Mex., Oreg., Utah, Wash., Wyo.; Mexico; Central America; South America; Europe; Asia (Middle East, Siberia); n Africa; Atlantic Islands (Iceland); Pacific Islands.

In Nunavut, var. vinealis is known from Banks Island.

Some collections of var. vinealis have elongate, very fragile apices, sometimes 2-stratose. Variety flaccidus was synonymized by P. Sollman (1983), but may be distinguished if needed by the leaves long, often 2.5 mm or longer, and crisped when dry, the distal margins plane. The peristome commonly falls with the operculum in the specimens seen, and may appear to be absent, but the operculum has twisted cells and is thin-walled.

The leaves of Didymodon vinealis var. vinealis may be nearly plane margined and quite fragile (Colorado: Jefferson County, Weber and Wittman B-110966, MO, COLO), with the appearance of variants of Trichostomum tenuirostre, but the distal laminal cells are distinctly reddish in KOH under high magnification (not yellow).