recircumscribed: A review of neighbouring Papaveraceae genera, including nom. et stat. nov. and , a large, Arctic-Alpine genus.

Papaveraceae tribus Papavereae includes an American and a mainly Eurasian group of genera. The latter is proposed here to include eight genera. Amongst these, the recently described genus is phylogenetically a sister group to , a genus from Himalaya and central China, which is reviewed here as including 95 species and 21 subspecies. By contrast, has a circumpolar northern alpine and Arctic distribution, including incompletely understood taxa, many threatened by climatic warming. Based on a review of literature and phylogenies, it is proposed here that includes 68 species and 29 subspecies. , , , and , 29 subspecies and four varieties are placed in here, 29 of these as recombinations, the remaining ones as nomenclatural novelties. A total of 21 existing names are placed into synonymy. The taxonomically challenging group from Central Europe is treated as comprising three species, with the remaining entities positioned at the subspecies level pending further studies. The much-studied Nordic species is treated with eight subspecies here, based on morphometric studies, whereas four accepted entities are provisionally recombined at the variety level. The name and the basionyms of , O.alpinasubsp.corona-sancti-stephani, O.alpinasubsp.degenii, , O.lapeyrouseanasubsp.endressii, O.lapponicasubsp.laestadiana and are lectotypified here. Two replacement names, Oreomeconalpinasubsp.markgrafiana and O.radicatasubsp.knabeniana, are introduced. , as currently understood, is recircumscribed here to represent four genera. The isolated sectionHorrida, from southern Africa, is raised to genus level with the new name and its only species is recombined as . Papaversect.Californica from California and adjacent Mexico is treated as the genus . The name has been applied to one of the two species of this group and we now recombine the other one as , based on an older basionym replacing . is accepted in its alternative position as the monotypic genus . As reviewed here, comprises 59 species and 14 subspecies and is only the third-largest genus in the group. Based on the distribution of its closest relatives and oldest sections, it is hypothesised here that arose in the western Mediterranean. Its poricidal capsule dehiscence serves as an excellent adaptation to seed dispersal in open, arid environments, possibly explaining its later success in the Türkiye-Caucasus-Middle East area, where its diversity both at species and section level is highest.