Korea Flora: Plant: Evergreen perennial. Rhizome: Short, oblique; leaves densely arranged. Stipe: 10-20 cm long; densely covered with light brown thin scales, continuing onto rhizome. Frond: Blade lanceolate; apex acute; margin entire; base cordate with auriculate lobes; 15-40 cm × 3.5-6 cm; midrib and abaxial surface with linear brown scales. Venation: Lateral veins slender, 1-2 times forked. Sori: Linear; arranged in pairs parallel to lateral veins from lower 1/3 of blade; appearing as single sori; indusium membranous, 7-25 mm long. Habitat: In shaded valleys; Ulleungdo Island, Byeonsan Peninsula, and Jeju Island. Note: Sori arrangement distinctive - paired along veins but appearing singular at first glance.

Japan Flora: Rhizomes ascending to short-creeping, clothed with basal remains of old stipes; stipes 10-20 cm. long, shorter than the blades, densely scaly while young, the scales membranous, deltoid-lanceolate, 5-8 mm. long, 1-2 mm. wide near base, long-filiform at the tip，brown, spreading, flexuous, very sparingly ciliate; blades chartaceous- herbaceous, simple, narrowly to broadly lanceolate, 15-40 cm. long, 3.5-6 cm. wide, acute, cordate-auriculate at base, entire to undulate, green above, slightly paler and with minute brown scales beneath while young, indistinctly hyaline on margin; costa with brown linear scales while young, especially beneath, the veins very slender, once or twice forked, the veinlets closely parallel, spreading, ending short of the margin; sori on upper two-thirds of blade, linear, paired, straight, spreading, parallel; indusia membranous, 7-25 mm. long, the pairs overlapping while young. Shaded slopes and rocks in mountains.

Hokkaido, Honshu, Shikoku, Kyushu. s. Kuriles, Sakhalin, Caucasus and Asia Minor to Europe, and N. America.