Herbs , perennial, rhizomatous, aromatic, glabrous to pubescent, in wet places. Stems simple or branched; vascular strands in 1(-2) ring(s). Leaves basal and/or cauline, alternate, simple; stipules present, adnate to petioles; petioles usually present. Leaf blade: margins entire. Inflorescences terminal, compact, conic spikes or lax, spikelike racemes terminal and/or opposite leaves. Flowers bisexual; perianth absent, each flower subtended by nonpeltate bract; stamens (3-)6(-8), hypogynous or epigynous; anther 2-locular; pistil 1, 3-5(-7)-carpellate; ovary 1- or 3-5(-7)-locular; placentation parietal or marginal; ovules 2 or 18-40; styles and stigmas distinct. Fruits capsules or schizocarps. Seeds 1 or many (-40); endosperm scanty; perisperm abundant; embryo minute.