Plants: small, green or yellow-green, often with reddish tinge. Stems: 0.4–1(–1.5) cm; rhizoids hyaline, pale yellowish brown, or red-brown. Leaves: loosely set, ovate-lanceolate to ovate, weakly concave, 0.6–1.5(–2) mm; base not decurrent; margins plane to weakly revolute basally, entire to serrulate distally, limbidium absent or indistinct, of 1 or 2 rows of elongate, incrassate cells; apex acuminate; costa percurrent to short-excurrent, awn slender; alar cells similar to adjacent juxtacostal cells; proximal laminal cells gradually rectangular, 2–4:1; medial and distal cells 50–70(–80) × 12–20(–24) µm, 3–4:1. : Specialized asexual reproduction by rhizoidal tubers, in clusters of 2–5 on short lateral rhizoids of main rhizoids at base of stem, yellow to orange-brown, pyriform, 80–150(–170) µm, cells 25–50 µm, smooth to slightly protuberant but not distinctly so. Sexual: condition dioicous. Capsule: unknown.
Disturbed soil of agricultural fields, landscaped or disturbed sites. low elevations (0-100 m). Que., Ariz., Calif., Nev., N.Mex., c, w Europe.
The many medium-sized yellow to orange rhizoidal tubers in clusters on short rhizoids at the stem base are diagnostic of Gemmabryum demaretianum. In the flora area, this species is probably introduced.