This name is a synonym of Rumex conglomeratus Murray.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 26001152) with original publication details: Bot. Arr. Brit. Pl. (ed. 2) 354 1796.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:697373-1.
This name was in version 1 of The Plant List, record tro-26001152, and has not been changed.