This name is a synonym of Rumex transitorius Rech. f..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50120985) with original publication details: Naturaliste Canad. 93(5): 645 1966.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:224465-2.
This name was in version 1 of The Plant List, record tro-50120985, and has not been changed.