This name is a synonym of Penstemon laricifolius subsp. exilifolius (A. Nelson) D.D. Keck.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50084212) with original publication details: Bull. Torrey Bot. Club 28(4): 230–231 1901.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:187382-2.
This name was in version 1 of The Plant List, record tro-50084212.