USE OF GAS CHROMATOGRAMS OF THE ESSENTIAL LEAF OILS OF THE GENUS EUCALYPTUS FOR TAXONOMIC PURPOSES

Using morphological observations, botanists have classified Eucalyptus species into characteristic series. A new vacuum distillation techniq ue has been employed to obtain the characteristic leaf oils, which are very close to their in vivo compositions, from 35 species belonging t o series Tetrapterae, series Torquatae and series Rufispermae. Accurat e gas chromatograms have been obtained for each species and three anal ytical techniques (principal component analysis (PCA), hierarchical cl uster analysis (CA) and linear discriminant analysis (LDA)) have been used to process these chromatograms to see if agreement with these cla ssifications could be achieved without using any auxiliary morphometri c data. Far the species chosen for the present study, linear discrimin ant analysis was the most successful in assigning species to their pre sent botanic classifications. These analytical methods were also used with some success in searching for groupings within a series and withi n a species.