xanthium spinosum l. is a highly invasive plant originated from south america throughout the world as well as in corsica island. the chemical composition of x. spinosum essential oils from 25 corsican locations was investigated using gc-fid and gc/ms. seventy-four components, which accounted for 96.2% of the total amount, were reported for the first time in the essential oil from aerial parts. the main compounds were eudesma-4(14),7-dien-1-ol (61; 21.3%), germacrene d (36; 8.8%) and cadalene (60; 8.7%). comparison with the literature highlighted the originality of the corsican essential oil and eudesma-4(14),7-dien-1-ol could be used as taxonomical marker to the systematics of the xanthium genus. the essential oils obtained from separate organs and during the plant vegetative cycle were also studied to gain more knowledge about the correlations between the volatile production and the phenological states of this weed. the production of oxygenated sesquiterpenes was predominant during the plant-flowering process. the study focuses on direct correlation between the chemical composition of individual 25 oil samples and the morphological differences of the plant. our results have gained more knowledge about the secondary metabolite production that occurs during the plant life, they could be interesting in order to manage the dispersal of x. spinosum.