This name is a synonym of Penstemon whitedii subsp. dayanus (Howell) D.D. Keck.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50126831) with original publication details: Fl. N.W. Amer. 5: 511–512 1901.
This name was in version 1 of The Plant List, record tro-50126831.