Mesochaete undulata

Mats on soil or rocks. Stems to 5 cm long, simple or sparingly branched, red-brown to chocolate brown at base, yellow-green toward apex, glabrous or with occasional red-brown rhizoids near base. Leaves complanate, ovate or fiddle-shaped, asymmetric, 1.8–5 mm long, 0.6–2.5 mm wide, undulate, crisped when dry; costa excurrent as an apiculum; apex rounded to bluntly acute; margins serrate for more than half-way down one side, undulate, with 5–9 rows of elongate cells to c. 160 μm long and to c. 7.5 μm wide forming a distinct border; laminal cells isodiametric, subquadrate to rounded-hexagonal, 8–20 μm long, 8–13 μm wide, becoming more elongated to 60 μm long, 18 μm wide at base. Seta 15–35 mm long, yellow to pale brown, smooth. Capsules erect, cylindric, curved, 4–5.5 mm long, Operculum bluntly rostrate, 0.9–1.1 mm long.