Description from Flora of China
Shrubs or subshrubs; stems hollow. Leaf margin shallowly dentate. Inflorescence a cyme, usually axillary, many flowered, dense, compact, headlike, shortly pedunculate or sessile. Flowers heterostylous. Corolla broadly funnelform, (4 or)5-lobed; lobes induplicate-valvate. Anthers dorsifixed near base, oblong; pollen grains 3-colpate. Disk ridged. Ovary with placentas at middle of septum; style prolonged; stigma oblong-fusiform. Fruit a 5-valved, slightly fleshy capsule. Seeds ovoid-oblong, slightly curved; testa spongy, longitudinally striate.
Two species: China, NE India, Laos, Myanmar, N Thailand, N Vietnam; two species in China.