This name is a synonym of Penstemon minor (A. Gray) D.D. Keck.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50287559) with original publication details: Proc. Amer. Acad. Arts 15(1): 51 1880.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:187727-2.
This name was in version 1 of The Plant List, record tro-50287559, and has not been changed.