Stems: 3 cm, 1–2 mm wide across leafy stem. Leaves: 1–2.5 × 0.4–1.2 mm; costa bulging abaxially; alar cells 9–19 × 9–14 µm, many on one side of costa and few on other; distal laminal cells 14–38 × 7–9 µm. Perichaetia: with leaf margins serrulate, especially distally, proximal laminal cells smooth, walls thin, distal cell walls thick. Seta: 0.6–1.2 cm. Capsule: 0.7–1.8 mm; operculum 0.5–0.7 mm. Phenology: Capsules mature winter.
Oak woods, swamps, base of trees, exposed roots, stumps, logs, limestone. low elevations (0-100 m). Ala., Fla., Tex., Mexico, West Indies, Central America, South America, Asia, Africa, Australia.
Stereophyllum radiculosum is recognized by its dull, complanate-foliate plants with simple or sparingly branched stems; leaves with a single prominent costa that bulges on the abaxial surface; abruptly acute to obtuse leaf apices; and short, rhomboidal laminal cells, usually with a single papilla over the lumina on both surfaces of the leaves.