Phylogenetics of the Irano-Turanian taxa of Limonium (Plumbaginaceae) based on ITS nrDNA sequences and leaf anatomy provides evidence for species delimitation and relationships of lineages

In a taxonomic and molecular phylogenetic study using nuclear ribosomal internal transcribed spacer (ITS) DNA sequences and anatomical data, the taxonomic status and relationships of Irano-Turanian Limonium spp. were investigated. The results of molecular phylogenetic analysis and anatomical synapomorphies showed that the Iranian Limonium spp. can be grouped into four major clades: (1) an unresolved clade including species of section Pteroclados as sister to all other Limonium spp.; (2) the L.axillare clade as sister to all Irano-Turanian and Mediterranean species; (3) a poorly supported clade consisting of species of section Nephrophyllum, L.caspium, L.bellidifolium and L.iconium of section Limonium subsection Hyalolepidae and the isolated species L.sogdianum (section Siphonocalyx) and L.nudum (section Platyhymenium); and (4) a well-supported clade including species of section Limonium subsection Limonium, part of section Sarcophyllum and L.lilacinum of section Sphaerostachys. The most diverse Mediterranean clade with many microspecies and apomictic taxa has no representatives in the Irano-Turanian area. The ITS results agree with distribution and some morphological and anatomical characters, giving strong support for separating L.perfoliatum and L.reniforme that have been considered conspecific in all recent taxonomic treatments. An updated key to all known Iranian Limonium spp., a synopsis of all species, with distribution maps, and descriptions and illustrations of Iranian species of section Nephrophyllum are provided. (c) 2013 The Linnean Society of London