Molecular and morphological revision of the A llium saxatile group ( A maryllidaceae): geographical isolation as the driving force of underestimated speciation

The taxonomic circumscription of A llium saxatile s.l. ( A maryllidaceae), widely distributed from I taly to C hina, has been controversial with the number of accepted species ranging from three to seven. The aims of this study include a morphological and molecular revision of the group, a thorough nomenclatural study of available names and the reconstruction of possible phylogenetic relationships in the A . saxatile group. We studied c . 2000 herbarium specimens and successfully sampled 86 accessions of the A . saxatile group and a few related species to reconstruct a molecular phylogenetic tree based on internal transcribed spacer ( ITS ) and two plastid DNA regions ( rpl32–trn L and trn L –trn F ). The monophyletic A . saxatile group consists of 15 geographical entities united in two geographically justified clades. Two yellow‐flowered species, A . obliquum and A . petraeum , were clearly nested in the A . saxatile clade in the ITS and plastid DNA analyses. The oldest names in the group, i.e. A . saxatile and A . globosum from the C aucasus, represent genetically identical populations and should be synonymized. The taxonomic conspectus in this article includes 15 species and a nothospecies. We describe five new species ( A. austrodanubiense sp. nov. , A. schistosum sp. nov. , A. cretaceum sp. nov. , A. montanostepposum sp. nov. , A. kirilovii sp. nov. ), a nothospecies ( A.  ×  agarmyschicum nothosp. nov. ) and raise a variety to species level ( A. rubriflorum comb. nov. ). © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society , 2015, 178 , 67–101.