Begoniaceae is a eudicot family of flowering plants with about 1400 species. They occur mostly in the subtropics and tropics in both the New and Old World. Recent molecular phylogenetic studies have reduced the family to two genera, Begonia and Hillebrandia which only occurs in Hawai`i. Hillebrandia has only one species, Hillebrandia sandwicensis.
Members of the Begoniaceae are perennial succulent herbs with rhizomes or tubers. They often form adventitious roots. The leaves can be more or less dissected. Flowers are unisexual and are mostly monoecious, which means that both male and female flowers occur on the same plant. Seeds are formed in winged capsules that split open to release the tiny seeds which are dispersed by wind.