This name is a synonym of Rumex stenophyllus Ledeb..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50079674) with original publication details: Enum. Pl. Transsilv. 580 1866.
This name was in version 1 of The Plant List, record tro-50079674, and has not been changed.