⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-50079832, with some changes.
This name is a synonym of Penstemon alpinus f. riparius (A. Nelson) Pennell.
The record derives from Tropicos which reports it as a synonym (record 50079832) with original publication details: Bull. Torrey Bot. Club 25(7): 379-380 379 1898.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:187737-2.