Physcomitrella patens (Hedw.) Bruch & Schimp.

Plants to 5 mm. Stems to 3.5 mm. Leaves to 2.5 × 1 mm, lanceolate or ovate-lanceolate to obovate, acuminate, not or weakly concave, margin of lanceolate leaves somewhat reflexed when dry, serrulate in distal 1/3, rarely below leaf median; costa ending near apex; proximal cells 65-135 × 15-45 µm, distal cells 36-66 × 12-27 µm; marginal cells sometimes longer that medial laminal cells, reaching 150 µm. Calyptra entire at base. Spores 21-33 µm.