Species divergence in Iris series Lacteae (Iridaceae) in Russia and adjacent countries based on chloroplast DNA sequence data

Abstract

In Russia, the species of the genus Iris L., series Lacteae Doronkin, the taxonomic structure of which still remains controversial, are found in the south of Siberia and the Russian Far East, as well as in other regions of Asia. Sequence analysis of three chloroplast DNA regions (rps4, trnL–trnF, and trnS–trnG) shows that, in Russia and adjacent countries, there are two genetically and geographically isolated Lacteae species. I. oxypetala Bunge grows in the south of the Russian Far East, and I. lactea Pall. grows in Siberia, Mongolia, and Kazakhstan. Genetic differentiation between the populations of I. lactea is extremely low and statistically insignificant (the fixation index Φ_ST = 0.057, P > 0.05), pointing to the unity of the gene pool and the absence of other Lacteae species in this area.