Japan Flora: Scandent, woody evergreen, the inflorescence, young branches, and underside of leaves pubescent; leaves elliptic to narrowly so, 4-8 cm. long, 2-4.5 cm. wide, obtuse or acute, short-petiolate; flowers white, changing to yellow, 2-25 cm. across; calyx thin, loosely pilose, 5-6 mm. long, the lobes obtuse and spreading; corolla-tube 7-8 mm. long, the narrow part as long as the broadened upper portion or somewhat shorter, the lobes obliquely obtriangular; anthers included within the tube; style short, not exceeding the calyx; follicles 10-15 cm. long.  May.

Honshu (centr. and w. distr.), Shikoku, Kyushu. Korea, and China.

Korea Flora: Evergreen climbing plant. Leaves: Opposite, shortly petiolate, narrowly elliptic or elliptic, obtuse or acute at apex, 4-6(8)cm × 1.3-3(4.5)cm, apex blunt. Young branches and leaf undersides pubescent. Petiole 3-5mm long. Flowers: In terminal or axillary cymes, densely pubescent. Flowers 2-2.5cm in diameter, white, changing to yellow; calyx 5-6mm long; petals obtuse, spreading in upper portion, slightly white-pubescent. Corolla tube 7-8mm long; anthers not reaching mouth of corolla tube; style approximately equal to or shorter than calyx. Fruit and Seeds: Follicles, 10-20cm long, diverging at right angle or greater.

Flowering Period: May to early June
Fruiting Period: Late August to mid-October
Distribution: Southern Honshu, Shikoku, Kyushu (Japan); Jeollanam-do, Jeollabuk-do, Gyeongsangnam-do, Jeju Island (Korea)