The flavonoids of Stenosiphon (Onagraceae)

Stenosiphon linifolius is a monotypic genus of the tribe Onagreae of the Onagraceae. The species is widespread in, but restricted to, the Great Plains of the United States. Three flavonol glycosides, kaempferol 3-O-rhamnoside, quercetin 3-O-rhamnoside and myricetin 3-O-rhamnoside, were found to occur in methanolic extracts of Stenosiphon leaves. Similar compounds are found in the leaves of such related genera as Oenothera and Gaura, but in the latter genera, additional flavonols exhibiting greater substitutional variation also are found.