Nephrodium expansum C. Presl, Reliq. Haenk. 1: 38. 1825; Dryopteris assimilis S. Walker; D. manshurica Ching; D. siranensis Nakai; D. spinulosa (O. F. Müller) Watt subsp. assimilis (S. Walker) Schidlay.

Plants 40-100 cm tall. Rhizome obliquely ascending or creeping, short, stout. Fronds caespitose; stipe densely scaly; scales pale brown to castaneous with a pale brown margin, glossy, ovate to broadly lanceolate, ca. 1.5 cm, membranous, apex acute; lamina longer than stipe, oblong, ovate-oblong, or subdeltoid, 25-50 × 12-35 cm, bipinnate-pinnatisect, base not narrowed, apex acuminate; pinnae 6-11 pairs, opposite or subopposite, basal pinnae largest, obliquely deltoid, shortly stalked, basiscopic pinnules distinctly longer than acroscopic ones, remaining pinnae oblong-lanceolate, rarely oblong-ovate, shortly stalked, apex acuminate; pinnules oblong, shortly stalked, apex acute; segments oblong, 2-4 mm wide, apex with aristate teeth. Lamina herbaceous, glabrous; veins pinnate, not forked, 3 or 4 pairs on each segment. Sori on upper part of veinlets; indusia orbicular-reniform, entire or slightly incised.

Dryopteris spinulosa var. morrisonensis Hayata (J. Coll. Sci. Imp. Univ. Tokyo 30: 422-423. 1911; D. morrisonensis (Hayata) Hayata), described from Taiwan, was treated as a synonym of D. expansa by Fraser-Jenkins (Bull. Brit. Mus. (Nat. Hist.), Bot. 14: 210. 1986).

Forests; 700-1800 m. Hebei (Wuling Shan), Heilongjiang, Jilin, Liaoning [Japan, Korea, Russia (Far East); Europe, North America].