This name is a synonym of Phlox longifolia subsp. humilis (Douglas ex Hook.) Wherry.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50321167) with original publication details: Fl. Bor.-Amer. 2: 72 18??.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:689755-1.
This name was in version 1 of The Plant List, record tro-50321167.