The hypothesis of introgression in Alpine Erigeron (Asteraceae): a multivariate morphological approach

摘要

From three Swiss Alpine regions, 180 Erigeron plants belonging or similar to E. alpinus, E. glabratus, E. neglectus, and E. uniflorus were analysed in respect to twelve morphological characters. The data was evaluated by correspondence and discriminant analysis to test the taxonomic delimitation of the species and the hypothesis of gene introgression. The results underline the difficulties in morphological separation of the Alpine Erigeron species in sympatric situations. In several cases interspecific hybridization and gene introgression are suggested, even if not all species seem likewise involved in this gene flow. At one locality an intermediate population exists in the absence of one of the supposed parental species. A relationship between theoccurrence of intermediate forms and the inhomogeneity of the habitat is found in another region.