Bryum chryseum Mitt., J. Linn. Soc., Bot. 12: 304. 1869.
Protologue: Guatemala. Volcan de Fuego, Godman & Salvin 304 (NY).
Bryum guatemalense Hampe ex C. Müll., Bull. Herb. Boiss. 5: 182. 1897. Protologue: Guatemala: Bernoulli sine loco speciali in Hb. Hmp.(BM, Ochi 1980).
Plants small, golden‑yellow, lustrous, in loose tufts, 3–5 mm high; rhizoids sparse. Leaves 0.7–1.0 mm long, imbricate with long, recurved apices when dry, imbricate when wet, concave, broadly ovate to deltoid; apices filiform‑acuminate; margins recurved below, plane or narrowly recurved above, not bordered, entire or lightly crenulate above, somewhat decurrent; costae long-excurrent, denticulate at apex; upper cells narrowly rhomboidal, firm‑walled, 44–90 μm long, basal cells quadrate to short‑rectangular, thick‑walled, 12–18 μm long. Dioicous. Setae 15–25 mm long, red. Capsules 2.5–4 mm long, narrowly clavate, neck slender and constricted, horizontal to inclined, light-brown becoming red with age; opercula 0.5 mm long, conic‑mammillate; annuli compound and revoluble; exostome teeth papillose, light-brown 350 μm high, endostome 320 μm high, yellowish to hyaline, basal membrane high, segments broad, widely perforate below, abruptly narrowing above, lightly papillose, cilia short to rudimentary, nodose. Spores 10–13 μm, faintly papillose. Calyptra not seen.