Use of gas chromatograms of essential leaf oils to compare eight taxa of genus Angophora (Myrtaceae): possible relationships to the genus Eucalyptus

摘要

Essential oils extracted from leaves of eight taxa of the genus Angophora were analysed. As expected, the individual components of these oils were essentially the same as those found in the Eucalyptus species from previous studies. In addition, as is also the case with the bloodwood eucalypts, only relatively low yields of oil were obtained. In all cases the cineole [eucalyptol] component was extremely small, but the oils of six of the eight taxa contained very large concentrations of the sesquiterpene bicyclogermacrene. A table of the 52 major oil components is included. Principal component analysis (PCA) was performed on data from the gas chromatograms (GC) of the essential oils and the resulting plots were compared with the cladistic classification of Thiele and Ladiges [see Cladistics (1988) 4, 23-42]. Because of the close relationship between genus Angophora and Eucalyptus subgenus Corymbia, the GC data for the eight Angophora taxa were combined with corresponding previously published data for eleven randomly chosen taxa from subgenus Corymbia and a PCA performed on the total system.