This name is a synonym of Penstemon violaceus (Brandegee) A. Nelson.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50107550) with original publication details: Bot. Gaz. 27(6): 456 1899.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:187739-2.
This name was in version 1 of The Plant List, record tro-50107550, and has not been changed.