⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-50079706, with some changes.
This name is a synonym of Penstemon angustifolius subsp. caudatus (A. Heller) D.D. Keck.
The record derives from Tropicos which reports it as a synonym (record 50079706) with original publication details: Minnesota Bot. Stud. 2: 34 34 1898.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:187256-2.