Description from Flora of China
Asplenium filix-femina (Linnaeus) Bernhardi var. attenuatum Wallich ex C. B. Clarke, Trans. Linn. Soc. London, Bot. 1: 492. 1880; Athyrium ensiferum Ching & H. S. Kung; A. filix-femina (Linnaeus) Roth var. attenuatum (Wallich ex C. B. Clarke) Beddome.
Rhizomes short, erect, apex densely clothed with red-brown, broadly lanceolate scales. Fronds caespitose; fertile fronds 35-60 cm; stipe upward stramineous, 5-17 cm, base ca. 2 mm in diam., similarly densely scaly, upward glabrate; lamina pinnate or 2-pinnate, lanceolate, up to 44 × 7-9 cm at middle, base gradually narrowed, apex acuminate; pinnae ca. 30 pairs, alternate, spreading, sessile, 7 or 8 pairs of lower pinnae gradually shortened, basal pinnae ca. 1.2 cm, apex obtuse, slightly reflexed; middle pinnae longest, linear-lanceolate, up to 4.5 × ca. 1 cm, base subtruncate, slightly widened, pinnatipartite almost to costae, apex acuminate; pinna segments ca. 14 pairs, subspreading, oblong, ca. 4.5 × 2.2 mm, basal segments slightly larger, connate to each other by narrow wing along costa, subentire at margin, apex obtuse and with 4 or 5 long teeth; veins visible abaxially, forked in segments. Lamina papery when dried, pale green, glabrate; rachis and costae stramineous abaxially, with very short subulate processes on adaxial side in upper part, squarrose-glandular hairs sparse abaxially. Sori oblong, basal acroscopic 2 or 3 pairs often horseshoe-shaped, 2 or 3 pairs per pinna segment; indusia brownish, oblong or horseshoe-shaped, membranous, erose at margin, persistent. Perispore surface without folds, with granular ornamentation. 2n = 80.
It remains to be clarified whether Athyrium attenuatum is distinct from A. dentigerum or its ecotype in alpine meadows.
Meadows on gentle mountain slopes; 2000-2400 m. W Sichuan, Yunnan [Afghanistan, Bhutan, N India, Kashmir, Nepal, Pakistan].