Although considerable adaptive radiation has resulted in varied morphology and habitat among the seven diploid species of Scaevola that are endemic to the Hawaiian Islands, members of the group show quite similar flavonoid profiles. All possess one apigenin glycoside plus several quercetin glycosides. Minor differences in glycosylation characterize some species. The similarity in flavonoid profiles supports an hypothesis of close systematic relationship among these taxa. The Hawaiian Islands are well known for possessing numerous examples of adaptive ra- diation in plants (Carlquist 1980). In many fam- ilies closely related species have diversified into different habitats and show remarkable radia- tion into different growth forms, leaf size and shape patterns, and inflorescence and floral features. Few studies of Hawaiian plants, how- ever, have centered on possible effects of adap- tive radiation on secondary compounds. Fla- vonoid compounds in particular, while used widely in systematic studies, have received scant attention with regard to patterns of adap- tive radiation. Gardner (1976) investigated fla- vonoid complements of Hawaiian Lipochaeta species, but there appear to be no other exam- inations of adaptive radiation of flavonoids in