Description from
Flora of China
Shrubs, subisophyllous or anisophyllous. Leaves opposite, petiolate; leaf blade margin entire. Inflorescences terminal thyrses; bracts and bracteoles greenish. Calyx unequally 5-lobed; posterior lobe largest, 2 lateral lobes smaller than 2 anterior lobes. Corolla tube basally cylindric and expanded distally into a throat; limb 2-lipped, lower lip 3-lobed, upper lip 2-lobed; lobes quincuncial in bud. Stamens 4, not connate, posterior pair shorter than anterior pair, inserted at base of throat; anthers 2-thecous; thecae parallel, inserted at different heights, dorsally pubescent, base spurred. Ovary with 2 ovules per locule; style basally sparsely pubescent. Capsule stipe absent or barely present; retinacula present. Seeds compressed, brownish pubescent.
Three species: China, Laos, Malaysia, Myanmar, Thailand, Vietnam; one species in China.
(Authors: Hu Jiaqi (胡嘉琪 Hu Chia-chi), Deng Yunfei (邓云飞); Thomas F. Daniel)