This name is a synonym of Oenothera deltoides var. cineracea (Jeps.) Munz.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50109255) with original publication details: Man. Fl. Pl. Calif. 681 1925.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:173497-2.
This name was in version 1 of The Plant List, record tro-50109255.