Bryol. Univ. 2: 719. 1827.
Lateral leaves slightly asymmetric, 1.5–2 × 0.8 mm; margins coarsely serrate distally; costa long-excurrent; medial laminal cells 13–16 µm. Dorsal leaves narrowly triangular-acuminate, 1 × 0.5 mm; costa long-excurrent; medial laminal cells 10–15 µm. Seta brown, 1.4–2.7 cm. Capsule brown, 3–4 mm; operculum obliquely rostrate, 2.5 mm. Calyptra tardily cucullate, 2.5–3 mm. Spores 13–15 µm.
Phenology: Capsules mature late Jan.
Habitat: Limestone, base of trees, rotted wood, humus, low and humid forests
Elevation: low elevations (0-50 m)
Fla., Mexico, West Indies, Central America, South America
Racopilum tomentosum is unmistakable due to the creeping stems, which are heavily tomentose ventrally in older portions, and the dimorphic leaves twisted-contorted when dry and spreading-erect in 4 rows when moist. Some of the Florida specimens have gametoecia (for example, Philips 97), but only a single collection with sporophytes is known from the flora area (Collier Co., Anderson & Crum 13440, Mosses of North America 595, DUKE, FLAS, LAF). Some duplicates of this issue may lack sporophytes.