Orthodontium gracile (Wils.) Schwaegr. ex B. S. G., Bryol. Eur. 4: 70. 1844.
Bryum gracile Wils. in Sm. & Sowerby, Suppl. Engl. Bot. 3: 2035. 1839. Protologue: Great Britain. On the sandstone rocks at Helsby and Frodsham, in Cheshire, being the northern termination of Delamere Forest, abundant, March 25th, 1833.
Plants small, yellowish green in tufts to 5 mm high; rhizoids moderately developed at base. Stem central strand absent. Leaves 3–4 mm long, erect to erect-flexuose, sometimes twisted when dry, linear-setaceous; apices narrowly acuminate; margins plane or weakly recurved below, not bordered, entire or weakly serrulate above; costa percurrent, stereid cells absent; upper cells linear‑fusiform, firm‑walled, 80–140 x 6–8 μm, basal cells reddish, enlarged, quadrate to oblong, thin-walled and bulging, alar cells not differentiated. Paroicous. Setae 4–10 mm long, yellowish. Capsules 1.5–2.5 mm long, oblong, oblong-cylindrical to sub-cylindrical, erect, smooth to lightly wrinkled when dry, constricted at neck, bordered at mouth by 3–4 rows of oblate cells; opercula conic-rostrate; peristome inserted within mouth, exostome yellow, smooth, endostome _ the length of the exostome teeth, yellow, smooth, basal membrane very low (1–2 rows of cells), segments stout, not perforate or keeled, cilia absent. Spores 12–16 μm, papillose. Calyptra not seen.