A combined molecular and morphological approach to the taxonomically intricate European mountain plant Papaver alpinum s.l. (Papaveraceae)—taxa or informal phylogeographical groups?

Papaver alpinums.l. is an extraordinarily polymorphic taxon distributed throughout southern and central European mountain ranges. We tested previous hypotheses about relationships and taxonomical status of the numerous described taxa within this species or species groupby applying different molecular approaches. In addition we re-evaluated morphological characters used in previous taxonomic treatments in the light of the molecular results. The ancestral sequence haplotypes were widespread and dominant throughout the Alps, whereas peripheral populations in other mountain rangeswere often characterised by haplotypes directly derived from the central haplotypes involving one or two mutational steps. The AFLP data corroborated the pattern of a ‘centrifugal radiation’ and additionally showed that most populations were genetically distinct, presumably due to the effect of genetic driftin small and isolated populations. The morphological data did not reveal clear patterns of variation; only the Pyrenean and Sierra Nevada populations differed in two non-overlapping and presumably independent characters. Altogether, our study implies that most previous taxonomic concepts of P. alpinum s.l. were highly artificial, and that either nearly all populations have to be raised to some taxonomic rankor that, preferably, no infraspecific taxa should be recognised at all. The only segregate possibly deserving taxonomic rank, based on both morphology and genetics, is the Iberian P. alpinum subsp. lapeyrousianum.