Japan Flora: Nearly glabrous, with a short stout stem or rhizome; fronds tufted, to 1.5 m. long or sometimes longer; stipes stout, fleshy, terete, green, about 2.5 cm. thick above the base，the basal portion dilated, obovate-orbicular, rounded on back, with a semirounded auricle on each side at top; blades oblong-ovate to ovate, bipinnate, to 1 m. long, 50-60 cm. wide; pinnae 3-6 pairs, alternate, the rachis swollen and jointed at base; pinnules 15-25 pairs, alternate, narrowly to broadly lanceolate, 5-10 cm. long, 1-25 cm. wide, acuminate, broadly cuneate to subtruncate at base, subsessile, minutely toothed, green above, paler beneath, the costa prominent on both sides, the veinlets many, parallel, spreading, distinct, usually once forked; sori oblong, about 1.5 mm. long, with 7-13 sessile ellipsoidal sporangia, each with an opening on the inner side, solitary on the veinlets near the margin of the pinnae. Woods in low mountains.

Honshu (Izu Isis" lzu Peninsula, Kii and Ise Prov.), Shikoku, Kyushu; rarer eastw. Ryukyus and Formosa.