Herbs, sometimes slightly woody at base, open or decumbent, matted or tufted, rarely glabrous. Leaves mostly decussate, rarely whorled, small, entire or variously incised or pinnatifid. Inflorescence an elongated to capitate spike, terminal, rarely axillary, usually densely many-flowered, often elongating after flowering. Flowers solitary in axil of a bract; calyx usually tubular, unequally and minutely 4- or 5-toothed; corolla-tube straight or slightly curved, lobes 5, slightly unequal and spreading; stamens in 2 unequal pairs, included in corolla-tube; ovary 4-locular with 1 ovule per locule. Fruit dry, separating at maturity into four 1-seeded mericarps.
About 250 species, mainly from temperate, subtropical and tropical America, 2 species from the Mediterranean and Near East region, widely cultivated; 12 species in Australia, 4 native, all others naturalised.