Mostly succulent herbs or shrubs; Lvs. opp. or alt. simple; stipules present, thin; fls. perfect, sep. 2 rarely 5; pet. 4-6 rarely more; stamens mostly 8 or many; ovary 1-celled, half inferior; stigma several-branched; ovules 2 to many on central free placentae; fruit circumscissile or pyxidate; seeds with curved embryo. About 20 genera and 350 species, chiefly American. One genus present in Guam.