Erysimum merxmuelleri

Erysimum merxmuelleri was one of a number of new Erysimum species first described by Adolf Polatschek in 1979.[4] Six of these, including E. merxmuelleri, were considered to be closely related and were reduced to subspecies of E. nevadense in Flora Europaea, a decision explained by Peter William Ball in 1990.[5] The six were treated as separate species making up the E. nevadense group or complex in Flora Iberica in 1993.[3] A molecular phylogenetic study published in 2014 included four of the species, although not E. merxmuelleri. The study did not support the view that the four were closely related, and authors concluded that the E. nevadense group did not have phylogenetic support.[6]