Glabrous, twining perennial. Leaves ovate to broad-ovate, mostly 5–10 cm long, 3–10 cm wide, apex shortly acuminate, mucronate, base cordate, margins undulate, basal lobes shallowly lobed; petiole 4–8 cm long. Flowers with peduncles 8–20(–30) cm long, much longer than petioles; bracteoles saccate, broader than long to broad-ovate, 2–3.5 cm long, apex rounded, truncate, emarginate or subacute, longer than and enclosing calyx, overlapping for nearly entire length; sepals 1.5–2 cm long; corolla 5–9 cm long, white or rarely pinkish. Capsule ovoid, 10–12 mm long. Flowers spring and summer.