Abstract
Changes in composition in leaf phenolics and volatile oils in Angophora costata (Gaertn.) Britten were investigated during the process of leaf maturation and over seasonal and diurnal periods. On a qualitative basis there was no variation in the leaf phenolics of the mature adult leaves. Quantitative variation in volatile oil composition during leaf maturation is significant. Sampling controls to exclude immature leaves were required. Quantitative changes in volatile oil composition over seasonal and diurnal periods were shown to be not significant in terms of systematic studies. The seasonal and diurnal patterns that were detected in volatile oil composition could not be conclusively related to any environmental parameter.