Description from Flora of China
Cardioteucris C. Y. Wu.
Herbs, subshrubs, or shrubs, erect or climbing. Leaves opposite, simple, entire or dentate, usually with glistening glands. Flowers in lax or dense cymes often aggregate into thyrses, rarely solitary. Calyx (4- or) 5- (or 6)-dentate or -lobed. Corolla short tubed, slightly 2-lipped, margin entire or dentate; lobes 5, spreading; lower lobe larger, concave, fringed. Stamens 4, often strongly exserted, inserted on apical part of corolla tube. Ovary 4-locular; ovules pendulous or laterally attached. Stigma 2-cleft. Fruit dry, usually dividing into four nutlets.
Sixteen species: C and E Asia, 14 species in China.