Infl. various, basically cymose; fls small, regular, perfect or unisexual; tepals 3-6, imbricate, often enlarged in fr.; stamens 6-9, anthers 2-celled. Ovary superior, 1-celled, subtended by annular nectariferous disk; ovule solitary, basal. Fr. a nutlike achene, lenticular or trigonous; seed with cop. endosperm. Herb, shrub or liane with us. alt. lvs; stipules ochreate. A cosmopolitan family with over 30 genera and ± 800 spp.

Herbs, shrubs, less commonly trees, erect or sometimes climbing. Stem nodes often swollen and jointed. Lvs usually alternate, simple. Stipules mostly forming a membranous or scarious ochrea (sheath). Infl. primarily racemose, spicate or paniculate, sometimes with secondary whorls or fascicles, usually many-flowered. Fls small, ☿ or unisexual, actinomorphic. Perianth 3-6-merous, in 1-2 whorls, often unequal, imbricate, free or connate, often persistent and accrescent. Corolla 0. Stamens (2)-6-9-(16); filaments free or united at base. Ovary superior, sessile, 1-locular, with a solitary, basal, erect ovule. Style 2-4-branched or styles free. Fr. a 3-angled, or 2-sided biconvex nut, often enclosed in persistent, commonly winged perianth. Seed with abundant mealy endosperm.