Leaf Flavonoid Chemistry of North American coreopsis (Compositae): Intra- and Intersectional Variation

Publisher Website
Google Scholar
Abstract
Six classes (flavones, flavonols, C-glycosylflavones, 6-hydroxyflavones, 6-hydroxyflavonols and 6-methoxyflavones) of foliar flavonoid compounds are the major constituents for 45 spp. in 11 sections of North American Coreopsis. Sections Calliopsis, Palmatae and Pseudoagarista are uniform in that all or most species display the same classes of compounds, whereas sections Coreopsis, Eublepharis, Euleptosyne and Pugiopappus exhibit pronounced interspecific variation. There are general correlations between presence of particular flavonoid classes and 3 groups of sections in North American Coreopsis. These 3 groups are viewed as 2 phyletic lines and a basal primitive group. There is also 1 monotypic section (Silphidium) of uncertain affinities. One phyletic line centered in the southeastern United States has 4 sections (Calliopsis, Coreopsis, Eublepharis, Palmatae), which contain a 6-hydroxyflavonol and 6-methoxyflavones; these flavonoid classes are not detected in other sections of North American Coreopsis. The 2nd phyletic line includes sections Tuckermannia, Pugiopappus and Euleptosyne, which occur primarily in California [USA] and contain C-glycosylflavones and 6-hydroxyflavones. The former class of compounds is unknown in the southeastern USA sections, and the latter occurs rarely. Section Silphidium of the southeastern USA has only flavones. Sections Electra, Anthysana and Pseudoagarista, representing the presumed primitive elements, consist of woody plants from the southeastern USA. Leaf flavonoid chemistry offers few clues to the origin of the 2 phyletic lines from the putatively more primitive plants of Mexico.