This name is a synonym of Oenothera macrocarpa subsp. incana (A. Gray) W.L. Wagner.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50109249) with original publication details: Boston J. Nat. Hist. 6(2): 189 1850.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:173189-2.
This name was in version 1 of The Plant List, record tro-50109249.