Description from Flora of China
Subshrubs or perennial herbs, glabrous or pubescent with simple and dendritic hairs. Roots stout, fleshy. Stems erect, obtusely angular, di- or trichotomously branched. Leaves solitary or paired, petiolate, simple, entire or coarsely dentate. Inflorescences solitary flowers in leaf axils. Flowers mostly nodding, somewhat actinomorphic or calyx 2-lipped. Calyx mostly funnelform, evidently 10-veined, 4- or 5-lobed; lobes unequal, variable in shape and length. Corolla campanulate, lobes quincuncial, included or exserted from calyx. Stamens shorter than corolla, inserted near base of corolla tube; filaments usually glabrous at base; anthers dehiscing longitudinally. Ovary conical, 2-locular, with a disclike nectary. Fruiting pedicel thickened or elongated. Fruiting calyx becoming enlarged, turbinate or campanulate, sometimes elongated beyond fruit, with main veins prominent and pleated. Fruit a globose or ovoid capsule, circumscissile above middle or dehiscent at apex. Seeds numerous, compressed.
Four species: China, Bhutan, India, Nepal; all four in China.