Revisiting infraspecific classification of Xerodraba patagonica (Brassicaceae) under different sources of evidence

Abstract

Xerodraba (5 spp.) is a genus of Brassicaceae restricted to the Southern Andes and Patagonia, of which X. patagonica includes subsp. patagonica and subsp. pycnophylloides. The latter was recently reduced from a species to subspecies based on morphological similarity to the former. However, for an adequate taxonomic ranking of these names (two species, one species with two subspecies, or one without subspecies), additional studies are needed, conducting analyses of different types of data. Here, we provide evidence for a new classification of these names by contrasting results obtained from different phylogenetic, ecological niche, and morphological analyses. For this purpose, we analyzed gene and species trees using nrITS and plastid data, compared the climatic niche and geographic range of both subspecies, and analyzed morphological variation associated with these names. Based on the results obtained, we here decided to synonymize subsp. pycnophylloides with X. patagonica.