Etymology Of Tsu-shima, Japan.

Description Rhizome: erect, short, scales broadly lanceolate, brown, often with blackish central portion, to 1 cm long, with irregular .
Frond: 45 cm high , evergreen, monomorphic , blade/stipe ratio: 3:2.
Stipe: grooved, scales at base similar to those on rhizome, those on upper portion narrowly lanceolate to linear, dark brown to blackish, continuing on the rachis, vascular bundles: 4 or more, in an arc.
Blade: 2-pinnate, lanceolate, glossy, linear to lanceolate scales below, no hairs.
Pinnae: 15 to 20 pair, lowest pinnae bending forward and downward; margins shallowly crenate, spiny; veins free, forked, black.
Sori: round, in 1 row between midrib and margin, indusium: peltate, attached centrally, shriveling, sporangia: dark brown.

Culture Habitat: slopes or rocky places in forests, often near streams. Distribution: China, Japan, Korea, Thailand, Indochina. Hardy to -20°C, USDA Zone 6.

Synonyms
Aspidium tsus-simense Hook.
Polystichum monotis Christ