Herbs. Leaves opposite, sessile. Flowers solitary, axillary. Bracteoles absent. Calyx 5-lobed almost to base; lobes valvate in bud. Corolla conspicuously 2-lipped; lower lip 3(or 4)-lobed, patent; upper lip 2-lobed, shorter than lower lip. Fertile stamens 2, posterior; filaments apically distorted; anthers hairy; staminodes 2, posterior, almost completely reduced. Capsule septifragal. Seeds ellipsoid; seed coat reticulate.

Two species: Japan, Korea, Russia; both in China.