Bryum tenuisetum Limpricht, Jahresber. Schles. Ges. Vaterl. Cult. 74(2): 4. 1897

Plants small, green or yellow-green, often with reddish tinge. Stems 0.4-1.5(-2) cm; rhizoids yellow. Leaves imbricate to loosely set, ovate-lanceolate to narrowly ovate, weakly concave, 0.4-1.5(-2) mm; base not decurrent; margins revolute proximally, serrulate distally, limbidium absent; apex acute to acuminate; costa excurrent to long-excurrent, awn stout; alar cells similar to adjacent juxtacostal cells; proximal laminal cells gradually quadrate to short-rectangular, 1-2:1; medial and distal cells 50-60(-70) × 12-14(-16) µm, 3-4:1. Specialized asexual reproduction by rhizoidal tubers, on long rhizoids in soil, yellow or rarely orange, ± spheric, (100-)120-180(-200) µm, cells 25-40 µm, smooth. Sexual condition dioicous or rarely synoicous. Capsule inclined or nutant, 2-3(-4) mm.

Capsules mature Apr-Jun (spring-summer). Damp to drying acidic soil; low to moderate elevations (0-600 m); B.C., N.B., N.S., Que.; Calif., Maine, Mass., Nev., N.Y., Wash.; Eurasia; Atlantic Islands (Tenerife); Australia.

Gemmabryum tenuisetum characterized by relatively large, yellow tubers with red cell walls and yellow rhizoids. In the flora area, this species is possibly introduced.