Nuphar lutea
Ernest Beal’s 1956 reappraisal of the "Nuphar" genus as a whole, North American together with Eurasian specimens, offered a new option -- one genus ("Nuphar") comprising just two species, “"Nuphar lutea", Beal” and “"Nuphar japonica",” the only taxon in Japan. Beal explained polymorphic variations observed in "N. lutea" specimens as nine subspecies which arose because of relatively minor geographical or ecological differences: