EXTERNAL FLAVONOIDS OF 12 SPECIES OF NORTH-AMERICAN EUPATORIEAE (ASTERACEAE)

The flavonoid aglycones excreted by and deposited on aerial parts of 1 2 species of tribe Eupatorieae, including 10 species of Eupatorium (na rrowly defined), Conoclinium coelestinum, and Brickellia eupatorioides , have been analyzed. The flavonoid pattern of Eupatorium is dominated by 6-O-methylated flavones, and there are relatively few differences between species including those of section Verticillata. In contrast, both Conoclinium and Brickellia were found to have significantly diffe rent flavonoid patterns. In Conoclinium, this included more highly O-m ethylated flavones. including the relatively rare compound 5,7,4'-triO H-6,3',5'-triOMe flavone. In B. eupatarioides this consisted of O-meth ylated flavonols that are a feature previously reported to be characte ristic of Brickellia and thus support the placement of the species in this genus.