This name is a synonym of Penstemon barbatus subsp. torreyi (Benth.) D.D. Keck.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 29204337) with original publication details: Prodr. 10: 324 1846.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:808325-1.
This name was in version 1 of The Plant List, record tro-29204337, and has not been changed.