This name is a synonym of Oenothera pratincola var. numismatica (Bartlett) R.R. Gates.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50130189) with original publication details: Cybele Columb. 1(1): 41–42 1914.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:173228-2.
This name was in version 1 of The Plant List, record tro-50130189.