Plants small, in compact, yellow-brown or green tufts. Stems (0.5--)1--2(--4) cm. Leaves erect spreading or falcate-secund, lanceolate, subulate, 2--3 mm; costa 30--55 µm wide at base, long-excurrent, rough near tip; distal laminal cells mostly quadrate (2--5:1), incrassate; basal laminal cells elongate, alar cells differentiated. Perichaetial leaves much larger than stem leaves. Seta short, 1--3 mm. Capsule immersed in perichaetial leaves, straight; peristome teeth spreading outward when dry. Spores 16--27 µm.

Capsules mature summer. Siliceous rock; high-alpine elevations; Greenland; Nfld., Yukon; Europe.

This rare Arctic-alpine species was once considered a variety of A. fulvella, but is distinguished by a short seta, large perichaetial leaves, and straight, immersed capsule. It has a costa that is more shortly excurrent than that of A. fulvella but longer than that of A. hyperborea.