The systematics of Ranunculus gmelinii and R. hyperboreus in North America
A consideration of the taxonomy of Ranunculus gmelinii DC. and R. hyperboreus Rottb. is presented. The role of phenotypic plasticity is indicated as a factor contributing to the range of morphological variation in these species and to the confusion found in their taxonomy. The present work, by a reexamination of representative material collected throughout the North American range of the species, and the use of controlled growth conditions, has suggested new limits for the species. This has resulted in modifications of the descriptions of the species and (or) the reduction of taxa to synonymy.Ranunculus hyperboreus Rottb. var. turquetilianus Polunin has been made a synonym of R. gmelinii DC.; R. natans C.A. Mey. var. intertextus (Greene) L. Benson has been made a synonym of R. hyperboreus Rottb.