Annual or perennial herbs, shrubs, rarely small trees, sometimes scandent. Leaves simple, alternate or opposite, without stipules. Inflorescence a dense head, loose or spike-like thyrse, spike, raceme or panicle, basically cymose, bracteate; bracts membranous and hyaline to white or coloured. Flowers bisexual or unisexual (monoecious or dioecious), usually regular, commonly bibracteolate and often in ultimate 3-flowered cymules, the lateral flowers of the cymules often sterile, modified into spines, bristles, scales or wings. Perianth uniseriate, membranous to firm and ultimately usually ± indurate especially about the base, usually falling with the fruit included; tepals free or ± fused into below, with or without alternating pseudostaminodes of various forms, sometimes almost completely monadelphous and 5-toothed at the apex with entire or deeply lobed teeth, some filaments occasionally without anther. Ovary superior, 1-celled; ovules 1–many, erect or frequently pendulous, placentation basal; style slender to obsolete; stigmas capitate to long and filiform. Fruit an irregularly rupturing or circumscissile capsule, commonly with thin lateral walls and a firm apex, rarely crustaceous or a berry. Seed globose to ovoid or lenticular, embryo curved or circular, surrounding the ± copious endosperm.
