Japan Flora: Habit: Evergreen perennial herb; rhizome short, thick, obliquely ascending; leaves fasciculate at apex.
Stipe: Densely scaly along with rachis.
Scales: Black to light brown, membranous; base broadened.
Blade: Ovate-oblong; apex gradually tapering to acute tip; dark green.
Pinnae: Elongate-oblong-lanceolate; obliquely ascending; lower ones sometimes long-stalked.
Scales on Rachis: Base bullate (inflated like pouches).
Scales on Pinnule Costa: Nearly round and bullate on abaxial surface.
Pinnules: Shallowly to deeply pinnatifid. Ultimate Segments: Margins entire, slightly revolute.
Sori: Medial between midvein and margin; indusium round-reniform, margins entire or sometimes hairy.
Habitat: Growing in shaded mountain areas.
Note: Distinguished by its dark green color, bullate scales on rachis and costa, and revolute segment margins.

[Translated from Flora of Korea by T.B. Lee]