Nuphar japonica
 Nuphar japonica is an aquatic plant species in the genus Nuphar found in Japan and the Korean Peninsula. It is endangered in Russia. The species was not accepted by The Plant List as of November 2013 which regarded it as an unresolved name.Nuphar × saijoensis (Shimoda) Padgett is a hybrid between N. japonica and N. pumila.N. japonica contains contains the alkaloids nupharidin 1-desoxynupharidin nupharamine methyl and ethyl esters of nupharamine.