Herbaceous or suffruticose perennials, rarely annuals. Stems leafy, much branched, pubescent with simple hairs or almost glabrous. Leaves not divided to pinnatisect, petiolate. Flowers in verticillasters borne in axils of upper leaves or in terminal oblong or capitate heads. Bracts entire or lobed, aristate or not. Flowers white, pink, blue to violet. Calyx tubular-campanulate, 15-nerved, straight or curved, bilabiate or scarcely so; upper lip equally 3-toothed or middle lobe dearly larger than laterals; lower lip with 2 teeth or apparently 4; base of teeth always with swollen folds at sinuses; tube glabrous within. Corolla bilabiate; tube gradually widening from base; upper lip straight or curved, subentire or bifid without longitudinal folds; lower lip 3-lobed with median clearly larger. Stamens 4, usually included under corolla upper lip, rarely exserted, didynamous with the posterior (upper) stamens slightly longer than the anterior (lower); thecae pilose or glabrous, bilocular, divergent. Style with 2 almost equal lobes. Nutlets 4, ovoid-oblong, smooth, weakly trigonous, apically truncate-rounded, frequently mucilaginous on wetting.