Plants soft green to glaucous, in lax to tight tufts. Stems 1--3(--5) cm. Leaves stiffly erect when dry, distal leaves occasionally divergent, linear subulate from an erect clasping base (base glistening white when dry), with well developed, firm shoulders; margins plane, entire proximally, serrulate to serrate distally, distal teeth often paired; costa excurrent in a slender tip, obscure in distal limb, low conic in cross section, appearing to fill the acumen; basal laminal cells thin-walled, distal cells 25--45 × 5--7 µm, prorulae relatively low. Sexual condition synoicous; perichaetial leaves somewhat longer than stem leaves, to 6 mm, more strongly clasping. Seta 8--30 mm. Capsule inclined to cernuous, subglobose to ovoid, asymmetrical, 1 mm, furrowed; operculum low conic, beak blunt; peristome double; teeth lanceolate, 300--400 µm, reddish brown, strongly transversely barred, finely papillose proximally, smooth above; segments smooth, irregularly lanceolate, 1/2-2/3 the length of the teeth and somewhat adherent to them, cilia absent or weakly developed. Spores 25--40 µm, coarsely papillose.

Capsules mature July--Nov. Soil or rocks; 0--3800 m.; Greenland; Alta, B.C., N.B., Nfld., Nunavut, Que., Yukon; Alaska, Calif., Colo., Idaho, Maine, Mich., Mont., Nev., N.H., Oreg., Utah, Wash., Wyo.; South America (Argentina); n and c Europe; Asia (Taiwan); n and c Africa.

Bartramia ithyphylla is essentially an Arctic-alpine species with disjunct populations in the high mountains of Africa and in austral South America. In the flora area it frequents tundra and montane forest habitats with occasional occurrence at moderate to low elevations at northern latitudes. The glistening white leaf base is distinctive. The obscure costa in the distal limb and the elongate distal laminal cells bearing low prorulae distinguish B. ithyphylla from other small species of the genus in the flora area.