Stems creeping for 2--5 cm, then ascending or suberect, 1.5--3 mm diam. Leaves monomorphic, dying back in winter, tightly clustered, (25--)40--105 cm. Petiole straw-colored, 3--20(--35) cm × 1--3 mm, at base with scales tan to reddish brown, ovate, glabrous. Blade elliptic, 20--70 cm, proximal 4--10 pinna pairs gradually reduced (smallest 5--20 mm), blade tapering gradually to pinnatifid apex. Pinnae 3--10 × (0.6--)1--2 cm, deeply pinnatifid to within 1 mm of costa; segments oblong to linear, oblique (sides slanted, not perpendicular to costa), entire to crenulate; proximal pair of veins from adjacent segments meeting margin above sinus. Indument abaxially of sparsely set hairs 0.2--0.7 mm on rachises, costae, and sometimes veins, also of numerous orangish, sessile to usually short-stalked glands on blade tissue; blades adaxially glabrous except along costae. Sori round, supramedial; indusia tan, glabrous or short-ciliate, sometimes also with glands; sporangia glabrous. 2 n = 54.

Terrestrial in woods and meadows, especially near springs, seepage areas, and streams; 0--1800 m; B.C.; Calif., Oreg., Wash.

Thelypteris nevadensis is named for the Sierra Nevada and, contrary to its common name, is not found in Nevada.