Integrative taxonomy in a rapid speciation group associated with mating system transition: A case study in the Primula cicutariifolia complex

•Accurate species delimitation is essential for biodiversity conservation.•Lack of empirical studies to assess the taxonomic problem of homostylous and its related heterostylous taxa at phylogenetic tip tree.•Multiple lines of evidence supported distyled and homostyled populations in Primula cicutariifolia complex were two separated evolutionary lineages.•Integrative taxonomy method help to delimit species in radiations associated with mating system transition.