Stems short- to long-creeping, 4--8 mm diam. Leaves monomorphic, evergreen, up to 2(--3) cm apart, (15--)50--160 cm. Petiole straw-colored, (5--)20--80 × (1--)3--6 mm, at base with brown, linear-lanceolate, hairy scales. Blade (9--)30--80 cm, broadest at base, gradually tapered to pinnatifid apex. Pinnae (2--)8--15(--20) × (0.6--)1--2.5 cm, incised 3/5--4/5 of width; segments oblong, rounded to acute at apex; proximal pair of veins from adjacent segments running to sinus, or nearly so. Indument abaxially of hairs mostly 0.3--1 mm on costae, veins, and blade tissue; veins adaxially with similar hairs but blade tissue usually without hairs, often with scattered yellowish, stalked glands 0.1 mm. Sori round, medial to supramedial; indusia tan, hairy, hairs 0.2--0.4 mm; sporangial glands obscure, yellowish, stalked, arising from sporangial stalks. 2 n = 144.

Roadsides, ditches, riverbanks, woodlands, limestone sinks; 0--100 m; Ala., Ark., Fla., Ga., La., Miss., S.C., Tex.; e,s Mexico; West Indies; Bermuda; Central America to Costa Rica; South America from Colombia to n Brazil.

Thelypteris kunthii occasionally hybridizes with T . augescens and T . ovata in Florida; hybrids with T . hispidula may also occur.