Elliptical Fourier Descriptors of Leaf Outlines: A Tool to Discriminate Among Aquilaria Species (Thymelaeaceae)

Leaf shape analysis of three Aquilaria species was undertaken using Elliptical Fourier descriptors (EFD) within a research plan­ting in tropical Australia. This approach was taken to develop a method for discriminating the species in the absence of repro­ductive traits or genetic analysis and as a morphological scale of leaf variation. Leaf outlines were analysed to distinguish variability between species. Principal components analysis and canonical discriminant analysis were applied to group the spe­cies based on 25 Fourier descriptors. Four components were required to explain 78 % of the variance and the first and second canonical functions discriminated three groups of spe­cies therefore EFD was a useful approach for analysing leaf out­line variability and distinguish species in the genus Aquilaria. This approach provides a rapid method that could assist in the species identification in Aquilaria where reproductive traits are absent.