Re-assessment of subspecific taxa in Astragalus section Anthylloidei (Fabaceae) based on molecular evidence

The taxonomic and phylogenetic status of several taxa previously recognized as subspecies inAstragalus sect. Anthylloidei is re-assessed based on DNA sequences and morphologicalfeatures. We focused on Astragalus ebenoides (subsp. ebenoides and subsp. naghadehensis),Astragalus murinus (subsp. murins and subsp. bornmuelleri), Astragalus remotiflorus (subsp.remotiflorus and subsp. melanogramma), Astragalus nigrohirsutus (=Astragalus remotiflorussubsp. nigrohirsutus), Astragalus submitis (=Astragalus submitis subsp. submitis) andAstragalus yushensis (=Astragalus submitis subsp. maassoumii). A total of 15 accessionsrepresenting 14 ingroups and one outgroup were analysed for nrDNA ITS and plastid DNA,rpl32 gene and rpl32-trnL(UAG) intergenic spacer. Phylogenetic trees were constructed usingneighbour joining, Bayesian and maximum parsimony methods. The phylogenetic analyses ofboth datasets revealed that the subspecies described formerly under each of the studied speciesare distinct and should be elevated to specific rank. The nucleotide sequence variationsobserved among different subspecies, along with morphological characters, providedappropriate criteria in setting the species boundaries. The new combinations and a diagnostickey to the studied species are provided.