THE TAXONOMIC SIGNIFICANCE OF NAPHTHOQUINONES IN THE DROSERACEAE

The distribution of the naphthoquinones 7-methylijuglone and plumbagin was studied among 63 species of the Droseraceae. Both compounds occur in Drosophyllum and Drosera; only plumbagin was found in Dionaea and Aldrovanda. Within Drosera, naphthoquinones support the classification s of De Candolle and Diels to some extent, with subgenus Drosera conta ining sections having 7-methyljuglone, often with plumbagin, and subge nus Ergaleium containing sections where plumbagin is predominant and 7 -methyljuglone rare or absent. Within subgenus Drosera, however, no na phthoquinones were found in three Australasian sections.