Title: Taxonomy and Evolutionary Relationships in the <I>Saxifraga rivularis</I> Complex
Abstract:Abstract In many arctic-alpine plant groups, reticulate evolutionary histories have resulted in problems with species delimitation and phylogenetic reconstruction. In the Saxifraga rivularis complex (...Abstract In many arctic-alpine plant groups, reticulate evolutionary histories have resulted in problems with species delimitation and phylogenetic reconstruction. In the Saxifraga rivularis complex (2n = 26, 52), the number of species accepted ranges from a single polymorphic one (S. rivularis s.l.) to several (the circumpolar S. hyperborea, the amphi-Atlantic S. rivularis, the three amphi-Pacific species S. bracteata, S. flexuosa, and S. arctolitoralis, and S. debilis in the Rocky Mountains). A combination of molecular (AFLPs), flow cytometrical, and morphological data from samples covering most of the distribution range was used to delimit taxonomic species and to unravel their evolutionary relationships. Four lineages with distinct morphological differences were recognized, representing four species: the diploids S. bracteata, S. hyperborea (including S. flexuosa), and S. debilis, and the tetraploid S. rivularis (including S. arctolitoralis). Based on a synthesis of the available data we provide a t...Read More