This study explores the taxonomy, systematics, and biogeography of Mertensia. Mertensia is a monophyletic genus of herbaceous perennials that comprises 62 species in Asia, Beringia, North America, and circumboreal locales, with a geographic center of diversity in the western United States. The phylogenetic relationships of Mertensia have been uncertain, with placement in various tribes in subfamily Boraginoideae. Moreover, Mertensia has presented considerable taxonomic problems especially centered in broadly circumscribed taxa. Using a phylogenetic approach, we evaluate relationships within Boraginaceae, infer evolutionary lineages, and address problematic taxonomic circumscriptions. We applied DNA sequence data...
