Phylogenetic analysis of Primula section Primula reveals rampant non-monophyly among morphologically distinct species

► A molecular phylogenetic analysis was conducted of Primula sect. Primula. ► Species trees show Primula elatior and P. veris as sister species. ► The oxlip Primula elatior is genetically heterogeneous and non-monophyletic. ► We examine the confounding effects of priors on Bayesian estimation of branch lengths.