Panarctic Flora


361222-23 The Ranunculus auricomus aggregate R. auricomus s. lat., R. monophyllos s. lat.

Geography: Amphi-Atlantic (E) - European - Asian - amphi-Beringian (W).

Notes: Rebristaya, Elven, and Yurtsev: The Ranunculus auricomus aggregate is a complicated and probably reticulate agamospermous group (e.g., Rousi 1955, 1956) where more than a thousand agamospecies have been described. These have variously been treated as (agamo)species or as (agamo)subspecies of four species: R. auricomus, R. cassubicus, R. fallax, and R. monophyllos. Ericsson (1992, 2001) discussed this complex thoroughly with references to other recent investigations. He considered the four collective 'species' named within R. auricomus s. lat. as grades (artificial form groups) rather than clades (evolutionary lines). Two of these are relevant in an arctic context: R. auricomus and R. monophyllos. We nevertheless accept them as two groups because the arctic representatives of the two groups are distinguished morphologically and geographically. Whereas the arctic representatives of "auricomus" probably represent several lineages, those of "monophyllos" may be a single lineage. Ericsson (1992, 2001) argued for species rank for the single entities, not least because subspecies is not an appropriate rank for agamospermous plants, because subspecific combinations in this case just is a complication, and because to combine the entities as subspecies under the four artificial 'clade' names has no evolutionary support.

The northern agamospecies are well investigated in some regions, unexplored in others. The main studies are Fagerström and Kvist (1980a, 1980b, 1983). The "auricomus" group is mainly temperate European and western Siberian with extensions into the Arctic on both sides of the North Atlantic. The "monophyllos" group is northern and continental Eurasian and extends across to western Alaska. We assume that the named agamospecies reported from the Arctic are only a small part of the total arctic assemblage and enter the single agamospecies in an abbreviated form.

Higher Taxa