This name is a synonym of Rumex microcarpus Campd..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50136152) with original publication details: Prodr. 14(1): 48 1856.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:697624-1.
This name was in version 1 of The Plant List, record tro-50136152, and has not been changed.