Trees, shrubs, herbs, or climbers, terrestrial or epiphytic; branches usually 4-angled; leaves opposite or whorled, simple, usually palmately nerved; stipules none; flowers regular, bisexual, mostly 4-5-merous (some 3-merous), solitary or in cymes or cymose panicles; calyx tubular, sometimes free, usually adnate to the then inferior ovary, often scabrid, scaly, pubescent, or tuberculate, sometimes smooth; petals distinct, imbricate, rarely very slightly connate basally, white, pink, purple, or yellowish; stamens twice as many as petals or the same number, often of 2 distinct kinds, sometimes distinguished by color as well as form, usually inflexed, the anthers 2-celled, basifixed, usually opening by 1 or 2 pores or by short slits, often appeandaged or/and the connective elongated or elaborated; ovary 4-5-celled, placentae axile, ovules many; fruit a capsule or berry; seeds small or minute. A large tropical family of 150 genera and perhaps 4200 species. Two genera are in Guam, both indigenous.