This name is a synonym of Phlox speciosa subsp. occidentalis (Durand ex Torr.) Wherry.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Pflanzenr. IV, 250: 74 1907.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:293332-2.
This name was in version 1 of The Plant List, record kew-2575357.