Examination by paper chromatography of the flavonoid content of the heartwoods and barks of sixty-one species of Acacia native to Australia, permits broad subdivision into four groups, depending on variations of the phenolic hydroxyl pattern (3',4',7_trihydroxy; 4',7-dihydroxy; 3',4',7,8-tetrahydroxy or 4',7,8_trihydroxy). Although these chemical subdivisions do not correspond with the broad morphological grouping of Australian Acacia into Phyllodineae and Bipinnatae, certain correlations are evident. All species of Botryocephaleae and Racemosae contain 3',4',7-trihydroxyflavonoids, associated in rare instances with 4',7-dihydroxyflavonoids. Similarly most Plurinerves and Juliflorae contain 3',4',7,8-tetrahydroxyflavonoids, but with notable exceptions amongst certain of the Juliflorae which contain only 4',7,8-trihydroxyllavonoids.