Phytologia 87: 67. 2005.
Plants green to yellow-green. Stems 0.5–1(–2) cm, slender, stringlike when dry, evenly foliate. Leaves folded adaxially along costa around stem when dry, ovate, weakly to strongly concave, 0.4–1(–1.5) mm; margins plane; apex broadly acute-rounded; costa percurrent to short-excurrent, apiculus occasionally present; proximal laminal cells abruptly quadrate, 1:1; medial and distal cells 8–12(–14) µm wide, (3–)4–5:1. Specialized asexual reproduction by leaf axil bulbils, bulbils 1 or 2 per axil, rounded, 200–750 µm, primordia present, leafy, arising from near base or mid bulbil, and by rhizoidal tubers, brown, spheric, 100–200 µm, cells smooth. [Capsule erect, red-brown, 1–2(–3) mm; hypophysis thick, rugose; peristome strongly reduced; endostome not or occasionally partly adherent to exostome, basal membrane low, segments reduced, split, perforations absent, cilia absent].
Habitat: Concrete, rock
Elevation: low elevations (0-10 m)
Fla., N.Mex., West Indies, Central America, South America, se Asia, Africa, Pacific Islands, Australia.
Gemmabryum exile is one of the most distinctive and easily identified species in the genus, with very slender stringlike stems and small infolded leaves that are ovate with plane margins.