This name is a synonym of Rumex hymenosepalus Torr..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50079652) with original publication details: Trans. New York Acad. Sci. 8(3–4): 73 1889.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:224400-2.
This name was in version 1 of The Plant List, record tro-50079652, and has not been changed.