Perennial, rhizomatous herbs, aromatic. Stems erect to prostrate, simple or branched. Leaves basal and/or cauline, alternate, simple and entire; stipules adnate to petioles, sometimes forming a sheath. Inflorescence terminal or leaf-opposed, in dense spikes or racemes, flowers subtended by a bract. Flowers bisexual; perianth absent; stamens 3–8 free or adnate to the ovary, anthers 2-locular; ovary superior, 3–5(–7)-locular, carpels sometimes distinct above, fused at base; ovules 2–13 per locule; styles as many as locules, free. Fruit a schizocarp or capsule; seeds 1 or many.
5 genera and 7 species from Central and Northern America, and Asia.