This name is a synonym of Penstemon canescens f. brittoniorum (Pennell) Fernald.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50316056) with original publication details: Acad. Nat. Sci. Philadelphia Monogr. 1: 222 1935.
⥇ A cross-taxon basionym link was ignored while processing this record,
see Penstemon brittoniorum Pennell.
This name was in version 1 of The Plant List, record tro-50316056.