Rhizomatous herbs; stems longitudinally ridged. Leaves cauline; petiolate. Inflorescence terminal or leaf-opposed, raceme or a lax spike. Flowers minute, white; stamens (3–)6(–8), longer than styles; ovary 3–4-locular, carpels distinct above, fused at base; ovules 2–4 per carpel. Fruit a schizocarp; mericarp dry, indehiscent; seeds 1 per carpel.
2 species from North America and Asia; 1 species sparingly established in Victoria.
