Plants dark green to brownish, somewhat glossy, tightly affixed to substratum. Stems 0.5-1 mm, erect, strongly radiculose. Leaves 0.5-5 mm, and somewhat crisped when dry, apex acute, the most proximal leaves reduced, laminal cells smooth, margins entire. Perichaetial leaves with smooth awn, 9-12 mm, lamina at awn base lacerate but not membranaceous. Capsule narrowly ovoid, 2-3 mm, stomata absent, mature capsules sheathed in penicellate perichaetium, awns extending more than twice the length of the immersed capsule. Spores 9-12 µm.
Sporophytes infrequent, capsules mature summer. Always on somewhat shaded humid rock surfaces, especially sandstones, conglomerate, and schist; moderate elevations (900-1000 m); Ala., Ga., Ky., N.C., Tenn., Va; Asia (China, India, Japan, Philippines, Sri Lanka).
Diphyscium mucronifolium is an example of an east Asian disjunctive species, and is found only as local, small populations.