CHEMOTAXONOMY OF THE ARGENTINEAN SPECIES OF GAILLARDIA

The biosystematic study of the Argentinian entities of the genus Gaill ardia Foug. have confirmed the differentiation of three species, Gaill ardia cabrerae, G. tontalensis and G. megapotanica, and the three vari eties of the latter (var. megapotamica, var. scabiosoides and var. rad iata). The chemotaxonomic study carried out on the above species and v arieties has confirmed the morphological findings and resulted in the isolation of the biogenetic precursor, the pseudoguaianolide 2 beta-hy droxy-2,3-dihydrohelenalin from G. megapotamica var. radiata.