Description from Flora of China
Asplenium yokoscense Franchet & Savatier, Enum. Pl. Jap. 2: 225. 1877; Aspidium subspinulosum Christ; Athyrium coreanum Christ, p.p.; A. demissum Christ; A. flaccidum Christ; A. pachysorum Christ; Dryopteris subspinulosa (Christ) C. Christensen.
Rhizomes short, stout, erect, densely clothed with yellow-brown, narrowly lanceolate scales at apex. Fronds caespitose; fertile fronds (30-)40-60 cm; stipe dark brown at base, upward stramineous, (10-)12-20(-25) cm, ca. 2.5 mm in diam., base densely scaly, upward glabrate; lamina pinnate-pinnatipartite to 2-pinnate with pinnules shallowly lobed, oblong-lanceolate, 18-45 × (8-)11-15 cm, base not narrowed, apex acuminate; pinnae 12-18 pairs, lower pinnae subopposite, upper pinnae alternate, spreading or slightly ascending, sessile, lanceolate; middle pinnae (3.5-)7-9 × (1.2-)1.5-2 cm, base truncate on acroscopic side, cuneate on basiscopic side, pinnate, apex long acuminate; pinnules ca. 12 pairs, oblong-lanceolate, up to 1 cm × ca. 5 mm, acroscopic base auriculate, basiscopic base decurrent and often adnate to wing of costa, margin shallowly lobed or dentate, apex acute; pinnule segments with 2 or 3 short teeth at apex. Veins visible abaxially, pinnate in pinnules, lateral veins forked. Rachis and costae abaxially stramineous, with sparse brownish, lanceolate small scales, with short thick spines on adaxial side at base of costae or costules. Sori orbicular or elliptic, medial; indusia brownish, elliptic, J-shaped, or horseshoe-shaped, membranous, entire, persistent. Perispore surface with prominent folds. 2n = 80.
Athyrium yokoscense var. kirisimaense (Tagawa) Li & J. Z. Wang was recorded in the key to the flora of NE China (in Fu Peiyun, Clav. Pl. Chin. Bor.-Orient. 36. 1995). It differs from var. yokoscense by the lamina 1-pinnate to 2-pinnate-pinnatifid, most pinnules stalked, and scales on rhizomes lanceolate to ovate-lanceolate. Further investigations are necessary to understand the infraspecific variation.
Rock crevices in forests; 100-2400 m. Anhui, Chongqing, NE Guizhou, Heilongjiang, Henan, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Shandong, Zhejiang [Japan, Korea, E Russia].