Examination of heartwoods from 14 species of Acacia collected from arid zones of Australia gave flavonoids in which the main components showed phenolic hydroxylation patterns typical of the subsections of the genus. In each case the main flavonoids were accompanied by minor components possessing hydroxylation patterns different from those of the main constituents. 3-Methoxyflavones were widely distributed in the species examined, and 8-methoxflavan-3,4-diols were detected in two species. Methylated flavonoids isolated include 7,8,4'-trihydroxy-3- methoxyflavone, 7,8,3',4'-tetrahydroxy-3-methoxyilavone, 7,3',4'-trihydroxy-3,8- dimethoxyflavone, and 7,3',4'-trihydroxy-8-methoxyflavonol. Attention is drawn to the similar chromatographic and light-absorption properties of fisetin, 8-methoxy- fisetin, and 7,8,4'-trihydroxyflavonol.