The flavonoids of Lithophragma (Saxifragaceae)

Abstract

Flavonoid profiles have been determined for all nine species of Lithophragma recognized by R. L. Taylor. Kaempferol, quercetin, isorhamnetin, and myricetin occurred in various combinations of 3-mono-, 3-di-, and 3-tri-glycosides, 3,7-diglycosides, and 7-monoglycosides although not all taxa had all such derivatives. The dihydrochalcone glucoside phloridzin was found in three populations of L. affine (of 18 examined) which marks the first report of this flavonoid type in the family. Other than the variation in phloridzin occurrence, flavonoid patterns were homogeneous within species. Each species exhibited a unique pattern of flavonol glycosides. Flavonoid data agree with Taylor's grouping together of L. parviflorum and L. trifoliatum and their close similarity to L. affine, and the placement of L. Cymbalaria in its own group. Flavonoid data do not, however, support the view that L. glaborum and L. tenellum are closely related, or that L. campanulatum may have arisen through hybridization between taxa similar to L. Bolanderi and L. heterophyllum.