Anictangium flaccidum De Notaris, Mem. Reale Accad. Sci. Torino 39: 254. 1836; Grimmia flaccida (De Notaris) Lindberg

Plants in cushions, olivaceous, light brown, or green. Stems 0.5-2 cm, central strand indistinct. Leaves erect or weakly curved when dry, ovate-lanceolate to ovate-triangular strongly keeled distally, 1.3-1.9(-2.4) mm, 1-stratose, rarely with a few 2-stratose striae distally; margins recurved to just before the apex, smooth, 2-stratose with 1-stratose patches; apices acute; costa excurrent as an often long, finely denticulate, straight or flexuose, and sometimes decurrent awn, often embracing part of the lamina, rarely percurrent, smooth; basal marginal cells short-rectangular, usually with transverse walls thicker than longitudinal walls; distal cells mainly ovate or short-rectangular, 7-10 µm wide, smooth, straight or slightly sinuose. Sexual condition autoicous. Capsule orange-brown or yellow-brown, cupulate, 0.6-0.9 mm; exothecial often irregularly angular, short-elongate or isodiametric, thin-walled or slightly thickened, occasionally with small trigones; rim red; stomata present; operculum mamillate; peristome absent or rudimentary, consisting of basal segments, to 30 µm, yellowish or orange-red, papillose. Spores 8-10 µm, granulose or verruculose.

Capsules mature late spring to early summer. Rock in open to shaded habitats; moderate to high elevations (1500-3200 m); Alta.; Colo., Idaho, Nev.; Eurasia; Africa; Atlantic Islands; Pacific Islands.

Schistidium flaccidum is characterized by long and broad-based awns, light-colored capsules with red rims, the rudimentary peristome, and the mamillate rostrum. For comparison to the similar arctic taxon 10. S. cryptocarpum, see the discussion thereunder.