⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-29204326, with some changes.
This name is a synonym of Penstemon cyananthus var. subglaber (A. Gray) N.H. Holmgren.
The record derives from Tropicos which reports it as a synonym (record 29204326) with original publication details: Syn. Fl. N. Amer. 2(1): 262 262 1878.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:290697-2.