形态特征：Twining perennials． Ｒoots carrot-shaped，up to2. 5 cm in diameter，branched or not． Stems over 1 mlong，glabrous． Leaves on main stem alternate; petiole1－2. 7 cm long，hispidulous; leaf blade ovate orovate-lanceolate，entire，densely hispidulous on bothsurfaces 2. 5－5 cm long，1. 5－3 cm wide，base cordate，truncate to rounded; those on branches similar，but smaller． Flowers solitary，terminal on mainstems and branches; pedicel 0. 5－4. 5 cm long，glabrous．Calyx tube hemispheric，adnate entirely tohypanthium，glabrous，10-ribbed; calyx lobes triangular-lanceolate，widest at base，entire，8 －10 mmlong，4－6 mm wide，glabrous，reflexed since anthesis．Corolla campanulate，white，glabrous，2. 8 cmlong; corolla deeply divided，lobes as long as tube，triangular． Stamens glabrous; filaments slightly dilated，equal to anthers in length． Style as high as stamens，stigma 3-fid，stigma lobes oblong． Fruit unknown．
