This species s. lat. occurs in Eurasia and N. America. Some lower taxa are distinguished, such as subsp. maritima (Kenyon) E. F. Warb. (syn.: var. arenaria Koch) in W. Europe and var. americana (Swet,) Fem. in eastern and partly central N. America. The map also includes the area of the closely related P. japonica Klenze and a few other Asiatic species as well as the wide range of the red-flowered taxa (P. asarifolia Michx) of P. rotundifolia s. lat. P. grandiflora Radius is mapped separately (no. 1440). P. rotundifolia belongs to the amphi-atlantic plants (Hultén, Amphi-atl., p. 142 and map 123). Together with the red-flowered taxa the species has a circumpolar distribution. Cf. also Meusel et al. 1978, map p. 324.