Description from Flora of China
Asplenium mongolicum Franchet; Athyrium mongolicum (Franchet) Diels; A. mongolicum var. purdomii C. Christensen; Nephrodium mongolicum (Franchet) Baker.
Rhizomes shortly creeping, ascending at apex, densely clothed with dark brown, subulate-lanceolate scales. Fronds caespitose; fertile fronds 30-50 cm; stipe brown at base, upward stramineous, 5-7 cm, 1-2 mm in diam., base slightly swollen, densely scaly, upward gradually becoming glabrate; lamina pinnate, suboblanceolate, 25-40 × 6-8 cm, base narrowed, apex acuminate; pinnae pinnatipartite, 20-24 pairs, lower 6 or 7 pairs of pinnae gradually shortened into triangular, auriculate small lobes, subopposite, sessile, spreading or slightly inclined, basal pinnae 1-1.2 cm × ca. 7 mm; middle pinnae broadly lanceolate, 3-4 × 1.2-1.5 cm at base, base truncate, sessile, pinnatipartite to costa, apex obtuse or acute, spreading, slightly curved; pinna segments ca. 8 pairs, basal acroscopic segments larger, oblong, 7-8 × ca. 5 mm, margin dentate, apex obtuse-rounded and crenate; upper segments shorter, approximate. Veins visible on both surfaces, pinnate in segments, lateral veins 3 or 4 pairs, simple, occasionally forked. Lamina herbaceous when dried, green or greenish brown, glabrate; rachis stramineous, occasionally with brown lanceolate scales. Sori large, mostly orbicular-reniform or horseshoe-shaped, 2 or 3 pairs per segment; indusia pallid, large, orbicular-reniform or horseshoe-shaped, membranous, margin ciliate or erose, persistent. Perispore with low folds. 2n = 80*.
Valleys, forests, wet rock crevices; 1200-2200 m. Gansu, Hebei, Heilongjiang, Henan, Hubei, Jilin, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shanxi, N Sichuan [Korea].