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.