Korea Flora: Habit: Evergreen perennial herb; leaves fasciculate at apex of thick, short rhizome. Stipe: 20-50 cm long, densely scaly. Scales: Linear to linear-lanceolate; margins entire; brown to dark brown; becoming narrower and shorter upwards, readily deciduous. Blade: Oblong to ovate-oblong; apex acute; 30-70 cm × 20-30 cm; bipinnate; adaxial surface glossy. Pinnae: Lanceolate to oblong; apex caudate; shortly stalked; abaxial rachis with bullate scales. Pinnules: Oblong to linear-lanceolate; apex rounded or acute; margins shallowly serrate. Sori: Arranged in single row; indusium round-reniform with entire margins. Distinctive Features: Young leaves and indusia with reddish-purple tinge Related Taxa: var. ambigens Nakai, Sori confined to upper half of pinnules, More deeply serrate margins
Habitat: Growing in forests of southern islands and Ulleung Island. Note: Distinguished by glossy surface, caudate pinna apex, and reddish-purple young parts.
[Translated from Flora of Korea by T.B. Lee]
Japan Flora: Rhizomes ascending, stout; fronds evergreen; stipes 30-60 cm. long, often reddish or brownish; scales linear to linear-lanceolate, nearly entire, brown to blackbrown, 10-15 mm. long in the basal, the upper ones smaller; blades broadly ovate to oblong, 30-70 cm. long, 15-35 cm. wide, acuminate, bipinnate, the rachis with linear-lanceolate to linear scales 2-3.5 mm. long; pinnae 8-12 pairs, sessile or nearly so, acuminate, the rachis with appressed ovate-saccate small scales with or without a linear tail; pinnules narrowly oblong to linear-lanceolate, 2-4 cm. long, 4-7 mm. wide, acute to rounded at apex, toothed, sometimes pinnately lobed, nearly glabrous above, with appressed hairlike short scales on veins beneath; sori mostly medhn, in 2 series on the pinnules; indusia often reddish while young, orbicular-reniform, entire, about 15 mm. across. Woods in low mountains and hills.
Honshu, Shikoku, Kyushu; very common and variable. Korea, Ryukyus, Formosa, China to Philippines.
var. caudipinna (Nakai) H. Ito. Blades longer, with ascending pinnatilobed pinnules to 6 cm. long; scales more dense. Warmer parts of our area.
var. purpurascens H. Ito. Stipes and rachis suffused purple. Kyushu (Yakushima). Ryukyus.
var. cystolepidota (Miq.) Nakai. Blade usually abruptly acuminate, the lowest pinnae wider with a wider posterior side; pinnules broader, often incurved-toothed to parted; sori smaller. Honshu (Kanto Distr. and westw.), Shikoku, Kyushu.
var. ambigens (Koidz.) Nakai. the blades elliptic, the pinnules obtuse, the fertile blades linear- oblong, often subendre and slightly crisped on margin. Honshu (Kanto Distr. and westw.), Shikoku, Kyushu; rare.