Species synoecious, monoecious or dioecious. Plants annual or perennial herbs, shrubs, or small trees, sometimes scandent, sometimes both stems and leaves fleshyl. Leaves without stipules, alternate or opposite, simple, sometimes succulent, sometimes reduced to a pair of small, opposite fleshy lobes at the top of the fleshy internodes. Inflorescences axillary or terminal, varying from or dense heads to loose or spikelike thyrses, spikes, racemes or panicles, basically cymose, ultimate units often 3-flowered, the lateral flowers sterile and modified into bracts, spines, bristles, or scales; bracts membranous and hyaline to white or variously colored. Flowers unisexual or bisexual, often subtended by 2 bracteoles; perianths usually radially symmetric, with 1-5 tepals; tepals free or more or less fused below, with or without alternating pseudostaminodes of various forms, membranous to firm and ultimately more or less indurate especially at the base, usually falling with the fruit; stamens 1-5, filaments sometimes fused together, entire or deeply toothed; ovaries usually superior 1-celled, sometimes semi-inferior, with 1-many ovules; styles slender to absent or almost so, unbranched and stigmas capitate or with 2-5 long, filiform branches. Fruits usually thin-walled utricles or irregularly rupturing or circumscissle capsules, rarely crustaceous or succulent, or berries;seeds globose to ovoid or lenticular; embryos curved or circular, surrounding the endosperm, testa membranous to crustaceous.
Amaranthaceae, as used here, includes about 170 genera and 2500 species. The family is tropical and subtropical in its distribution and is particularly well represented in dry and saline areas. Several members are widespread weeds.
