This name is a synonym of Phlox tenuis (A. Gray) E.E. Nelson.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50323256) with original publication details: Proc. Amer. Acad. Arts 8: 257 1870.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:193476-2.
This name was in version 1 of The Plant List, record tro-50323256, and has not been changed.