Nov. Guinea, n.s., Bot. 2: 123. 1914. Amblystegium halleri (Hedw.) C. E. O. Jensen, Danmarks Mosser 2: 73. 1923. Campylium halleri (Hedw.) Lindb., Musci Scand. 38. 1879. Hypnum halleri Sw. ex Hedw., Sp. Musc. Frond. 279. 1801. Type: Switzerland.
Plants slender, elongate, golden yellowish, glossy, in densely caespitose mats. Stems prostrate, 2–5 cm long, subpinnately branched; pseudoparaphyllia few, filamentous or foliose. Stem leaves slightly falcate-secund, 0.6–0.8 mm × ca. 0.5 mm, rounded-ovate at base, abruptly narrowed to a shortly, strongly squarrose, channeled acumen; margins serrulate above; costae very short, double; median leaf cells linear, 30–50 μm × 3–5 μm; basal cells yellow, rectangular, thick-walled; alar cells slightly differentiated, quadrate or shortly rectangular, thick-walled, yellowish. Autoicous. Inner perichaetial leaves elongate-lanceolate, ca. 3.5 mm × 0.5 mm, plicate, gradually narrowed to a long, subulate acumen; costae short or absent. Setae 15–20 mm long, reddish; capsules 1.5–1.8 mm, inclined or horizontal, cylindrical, often arching curved; endostome segments carinate; cilia 2–3, short, nodulose. Spores 10–14 mm in diameter, papillose.