This name is a synonym of Penstemon canescens (Britton) Britton.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50316055) with original publication details: Mem. Torrey Bot. Club 2(2): 30–31 1890.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:187586-2.
This name was in version 1 of The Plant List, record tro-50316055.