This name is a synonym of Rumex pseudonatronatus (Borbás) Murb..
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Bot. Not. 1899: 17 1899.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:60434380-2.
This name was in version 1 of The Plant List, record kew-2430085, and has not been changed.