The chalcones are common in mixtures with aurones to generate the anthclor pigment in the Compositae. In nature, it is uncommon to find them without substitutions, but hydroxylated have been described in wood and peels of trees in the genus Acacia, Rhus, Macherium, and Adenanthera. Flavonols are ubiquitous in woody angiosperms, common in shrubby angiosperms, and exceptionally in inferior plants.