This name is a synonym of Penstemon heterodoxus var. cephalophorus (Greene) N.H. Holmgren.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50119022) with original publication details: Leafl. Bot. Observ. Crit. 1(5): 79 1904.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:312126-2.
This name was in version 1 of The Plant List, record tro-50119022.