Fls small, regular, perfect, in clusters, spikes or racemes; tepals 3-5, scarious, free or nearly so, imbricate. Stamens us. 5, often with up to 5 staminodes, opp. tepals; filaments ± united towards base. Ovary superior, 1-celled; styles very short or 0; stigmas us. capitate. Ovules us. solitary. Fr. transversely dehiscent or ind.; seeds smooth, embryo annular, endosperm cop. Annual to perennial herbs with alt. or opp. exstipulate lvs. Widespread family of some 50 genera and 500 spp.

Fls very small, often bracted, greenish, perfect or unisexual, regular or nearly so. Per. 3-5-lobed or 0; in ♀ often accrescent; stamens us. 3-5, free, anthers 2-celled. Ovary 1-celled, ind.; embryo annular. Annual to perennial herbs or shrubs with mostly alt., simple, exstipulate lvs. A cosmopolitan family of some 75 genera and over 500 spp.

Annual or perennial herbs, rarely shrubs, lianes or trees. Lvs alternate or opposite, simple, exstipulate. Fls small, ☿, arranged in spikes, heads or racemes, usually conspicuously bracteate; bracts and bracteoles often scarious. Tepals (corresponding to sepals) (2)-3-5, free or nearly so, imbricate, nearly always scarious. Petals O. Stamens (1)-5, opposite the tepals; filaments united basally; staminodes present or 0. Ovary superior, 1-locular; ovules usually solitary; stigma capitate or 2-3-lobed. Fr. (utricle) indehiscent or with circumscissile dehiscence; pericarp usually dry and membranous, less commonly fr. baccate. Seeds globose, ellipsoid or compressed, smooth or verrucose, endospermic.

Monoecious, ☿, or dioecious herbs or shrubs, rarely small trees, often succulent, glabrous or with vesicular hairs giving a farinose appearance. Lvs generally alternate, sometimes opposite, simple, exstipulate. Fls solitary or in dense cymes aggregated in a spike or panicle, bracteolate, often very small, usually actinomorphic, greenish. Calyx 3-5-lobed, rarely 0, often accrescent at fruiting; lobes usually imbricate. Petals 0. Stamens usually as many as perianth lobes and opposite to them, usually free. Ovary superior, sometimes immersed, 1-locular. Ovule solitary, basal, erect or pendent. Stigmas (1)-2-3. Fr. usually an achene, rarely a berry, occasionally with circumscissile dehiscence. Seed often erect, compressed in 1 plane, non-endospermic, or with endosperm and then embryo curved or coiled round it.