Stems short-creeping to suberect, 5--8 mm diam. Leaves monomorphic, evergreen, clustered, 20--55(--80) cm. Petiole straw-colored, 5--18(--25) cm × 1--3 mm, at base with brown, lanceolate, stellate-hairy scales. Blade 15--40(--55) × 5--10 cm, proximal 2--5(--10) pairs of pinnae gradually reduced, blade gradually narrowed distally to a pinnatifid apex. Pinnae 18--25 pairs, 2--5(--8) × 1--1.5(--2) cm, deeply serrate to incised nearly 3/4 of width, distal pinnae often strongly adnate; segments of rather harsh texture, somewhat oblique, rounded-deltate to often acute; proximal pair of veins from adjacent segments united below sinus with excurrent vein. Indument on both surfaces of numerous, sessile or short-stalked, stellate hairs 0.1--0.2 mm on costae, veins, and blade tissue; rachises and costae sometimes with longer simple hairs to 0.8 mm abaxially. Sori round, medial to supramedial; indusia tan, densely stellate-hairy; sporangia glabrous. 2 n = 144.

Terrestrial or on rock in limestone hammocks; 0--50 m; Fla.; West Indies in the Greater Antilles.

In the flora Thelypteris sclerophylla is known only from Dade County, Florida, where it is rare.

C. Christensen (1913), C. V. Morton (1951), and D. B. Lellinger (1985) have attributed the basionym to Kunze in Sprengel, but Sprengel clearly credited Poeppig, rightly or wrongly. Sprengel's original description also differs in a number of details from that by G. Kunze (Linnaea 9: 92. 1834), so that Kunze's later attribution of the basionym to himself cannot be accepted.