Plants 1-1.5 m tall, glabrous or glabrescent. Roots stout, yellow-brown, pale yellow within. Petiole 0.5-1(-1.5) cm; leaf blade ovate or elliptic, 8-15 × 3-6 cm, papery or submembranous, base cuneate or slightly decurrent, margin entire, sinuate, or sometimes 1-3-toothed, apex acuminate. Pedicel ca. 2 cm. Calyx 3-4.5 cm, with 10 erect veins, glabrous or sparsely pubescent abaxially, irregularly 4-or 5-lobed; lobes narrowly deltate, 2 (or 3) of which are longer and larger, 2-2.5 cm. Corolla pale yellow-green, sometimes purplish; lobes purplish, similar to calyx in shape, barely exceeding calyx to about twice as long, 2.5-3(-4) cm, pubescent, with a purple spot at base of tube abaxially. Stamens included, about half as long as corolla; anthers 5-5.6 mm. Fruiting pedicel to 7 cm, curved. Fruiting calyx 3.5-4.5 cm. Capsule nodding.
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