⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-50119025, with some changes.
This name is a synonym of Penstemon attenuatus var. palustris (Pennell) Cronquist.
The record derives from Tropicos which reports it as a synonym (record 50119025) with original publication details: Notul. Nat. Acad. Nat. Sci. Philadelphia 71: 8–9 8 1941.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:187641-2.