This name is a synonym of Penstemon multiflorus (Benth.) Chapm. ex Small.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50338177) with original publication details: Prodr. 10: 327 1846.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:187712-2.
This name was in version 1 of The Plant List, record tro-50338177, and has not been changed.