A Numerical Analysis of Flavonoid Variation in Arnica Subgenus Austromontana (Asteraceae)
Species of Arnica subgenus Austromontana produce a total of 23 leaf flavonoids, including simple and methylated flavone and flavonol glycosides as well as highly methylated flavone aglycones and a 6-hydroxylated flavone. Most of the taxa exhibit considerable interpopulational variability, with the number of compounds per population ranging from 2 to 14. Analysis of flavonoid variation in 1 3 populations representing all 9 species of the sub-genus was carried out using cluster analysis, principal components analysis, and binary discriminant analysis. Results indicate the flavonoid profile of the very rare A. viscosa is the most distinctive in the subgenus. Although exhibiting considerable interpopulational variability, all populations of A. gracilis, a hybrid taxon, form a very distinct and cohesive group, supporting its recognition at the specific level. Additionally, chemical diversification from A. cordifolia has taken place largely in the Klamath region of Oregon and California. The range of variability exhibited by A. cordifolia is reflected in these Klamath region derivatives.