Japan Flora: Somewhat crisped-hairy; stems slender, erect on lower half, much elongate and scandent, 40-100 cm. long; leaves of the lower erect portion larger, membranous, broadly lanceo­late to narrowly oblong-ovate, 5-12 cm. long, 1-2 (-3) cm. wide, gradually acuminate, rounded to shallowly cordate-trun­cate at base，the petioles 2—4 mm. long; inflorescence in upper axils; flowers yellow, 7-8 mm. across, few, in umbels, the peduncles nearly absent, the pedicels 3-4 mm. long, usually shorter than the flowers; corolla-lobes narrowly ovate, glabrous on both surfaces, obtuse; corona-lobes depressed-deltoid, about half as long as the gynostegium; follicles broadly lanceolate, glabrous, 4-5 cm. long, 5-7 mm. wide; seeds ovate-elliptic, about 5 mm. long, winged.  July-Sept. Mountains

Hon­shu (centr. and n. distr.). Korea

f. abulcumense (Koidz.) Hara. Flowers purple.