The Essential Oil Composition of Trachymene incisa Rudge subsp. incisa Rudge from Australia

Trachymene incisa subsp. incisa is an Australian endemic taxon that varies greatly in the abundance and length of the leaf trichomes. The essential oil composition of five populations of this subspecies, three corresponding to the typical glabrous form and two of the particularly hairy variant, has been analyzed in an attempt to determinate if that variability is also reflected in their composition. The oils have been extracted by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography coupled to Mass Spectrometry (GC–MS). The essential oils of T. incisa subsp. incisa were characterized by the high amount of sesquiterpenes that were the major fraction. The sesquiterepene hydrocarbons were significantly higher in the hairy variant in comparison to the glabrous one. According to the main compound, three different chemotypes were found: I.—β-selinene + bicyclogermacrene and II.—γ-bisabolene + α-pinene for the typical glabrous variant and III.—bicyclogermacrene + β-caryophyllene for the hairy variant.