Plagiobryum zieri (Hedw.) Lindb., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 19: 606. 1862 . Bryum zierii Hedw., Sp. Musc. Frond. 182. 1801. Protologue: Scotland. Ad aggeres humidos in alpibus Scotiae.
Plants small, tufted, simple or sparsely branched, often with slender innovations; stems to 3 mm high, red; rhizoids reddish orange to brownish, roughened. Leaves crowded, 1–2 mm long, erect to imbricate, turgid to julaceous, soft, ovate to broadly ovate-lanceolate, not or weakly decurrent; apices acute; margins plane to irregularly and loosely recurved, entire to serrulate above; costae ending in the apex to percurrent; cells lax, thin-walled, upper cells hexagonal to rhomboidal 50–80 x 20–30 μm, marginal cells longer and narrower, basal cells short-rectangular, 40–60 x 12–24 μm. Dioicous. Perichaetial leaves lanceolate, upper cells linear-rhomboidal to elongate, firm-walled. Setae short, stout, curved, 6 mm long, reddish brown. Capsules horizontal to pendent, 4 mm long, strongly asymmetric, narrowly clavate, with a long, well-developed neck as long or longer than urn; stomata superficial; opercula low-conic, apiculate, 0.8 μm long; annuli revoluble, of 2–3 rows of cells; exostome teeth slender, reddish brown, striate-papillose below, whitish hyaline, smooth above, endostome reduced, whitish yellow, basal membrane _ the height of the exostome, segments slender, narrowly perforate, cilia rudimentary. Spores 30–36 μm, ellipsoid, coarsely papillose.