Sorbus ×thuringiaca, the correct name for the diploid hybrid between Sorbus aria and S. aucuparia (Rosaceae)

A complicated assemblage of names for taxa of hybrid origin between the Sorbus aria agg. and S. aucuparia (S. subg. Soraria) was analysed with the aim of separating the names of diploid hybrids from those of polyploid apomictic species and evaluating them nomenclaturally. Several names were found to be invalid, illegitimate, acceptable only for cultivated clones (cultivars), or representing indefinite taxa. Only one legitimate name was found to be available as the correct name of the diploid hybrid S. aria s.str. x Sorbus aucuparia, i.e., S. xthuringiaca, with a newly designated lectotype.