This name is a synonym of Rumex paucifolius Nutt..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50079644) with original publication details: Rep. (Annual) Missouri Bot. Gard. 1891: 78 1892.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:224438-2.
This name was in version 1 of The Plant List, record tro-50079644.