Leaf extracts of Erythroxylum australe O. E. Schulz, produced six O-conjugated flavonoids. Two of the flavonoid aglycones were isoflavones, two were isoflavanones, one a flavanone and the remainder a flavonol (quercetin). The major glycosides of these flavonols included mono- and dirhamnosides and mono-glucosides with either 2, 7 or 4' linkage or a combination thereof. This population of flavonoids from E. australe suggests ancestry to Erythroxylum ulei and possibly more remotely to E. coca and/or E. novogranatense. These flavonoids may be used as chemotaxonomic markers for the taxon.

Key words: Erythroxylum australe, Erythroxylum chemical relationships, flavonoids