The record derives from WCSP (in review) (data supplied on ) which reports it as a synonym with original publication details: Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 3: 78 1937.
Full publication details for this name can be found in IPNI:
This name record (from WCSP (in review)) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Rheum potaninii in version 1 of The Plant List.