Herbs. Leaves opposite (or basal ones subverticillate). Flowers usually small, in few-flowered verticillasters, forming a terminal raceme-like inflorescence. Calyx turbinate (more or less saccate in fruit), 5-toothed, 2-lipped; upper lip 3-lobed, lower lip obtuse, strongly incurved and gibbous in fruit. Corolla tube exserted, spurred at the base; limb 2-lipped, upper lip 3-4-lobed, recurved, lower lip entire, concave. Stamens 4, in 2 pairs; filaments free, inserted at two levels. Style shortly 2-fid. Nutlets orbicular, often finely pitted.