Herbs, shrubs, trees or vines; leaves usually opposite, sometimes spiralled or in false whorls, simple; stipules none; sometimes spiny; sometimes fleshy or tuberous; flowers variously disposed, mostly regular, bisexual or unisexual, sometimes monoecious; involucre of often showy colored bracts; perianth of 3-5 tepals, tubular; fruit an anthocarp by fusion of part of the perianth tube; stamens 1 to many; ovary semisuperior, subsessile, 1-celled; ovule 1, basal. 30 genera, 290 species. Four genera in Guam, two of them native.