Erect, rarely procumbent or ascending herbs or shrubs. Leaves short to long petiolate, lamina ovate to elliptic, entire, rarely crenate or crenulate, often with cystoliths. Flowers sessile or pedicellate, white, pink or purple in terminal or axillary congested spikes or panicles, sometimes solitary or in thyrsoid cymes; bracts linear or subulate to large, foliaceous and imbricate; bracteoles 2, linear-lanceolate, occasionally absent. Calyx deeply 4-5-lobed, lobes usually narrow, equal or ± unequal, narrowly scarious, obtuse to acuminate. Corolla bilabiate; tube often narrow, funnel-shaped, straight or incurved; upper lip narrow, ± galeate, entire to bifid; lower lip broad, ± patent or recurved, shallowly to deeply 3-lobed, imbricate. Stamens 2: filaments fillifrom, ± dilated basally, attached near the middle of tube, slightly exserted; anthers dithecous, thecae usually unequal, oblong or linear, occasionally curved or reniform, superposed or almost parallel, one or both cells apiculate or calcarate, staminodes absent. Ovary hairy, stigma minutely unequally 2-lobed. Capsule oblong, ovoid or obovoid-clavate, contracted and solid below the middle to form the stipe, usually 4-seeded. Seeds on curved retinacula, compressed, orbicular-lenticular, occasionally subglobose or ovate, rough, tuberculate or smooth.