Trees, shrubs, or herbs; leaves opposite or whorled, or alternate, simple, entire, stipulate; flowers perfect; sepals 3-16, inserted on the margin of a tubular receptacle; petals and sepals free, equal in number, inserted on margin of receptacle; stamens usually twice as many petals, inserted on the inner side of the receptacle; ovary superior, 1-6 celled; placentae axile; ovules 2-many; fruit a capsule. About 20 genera and nearly 500 species, tropical and subtropical, a few warm-temperate. Four genera in Guam, one native.