⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-50079702, with some changes.
This name is a synonym of Penstemon rydbergii var. aggregatus (Pennell) N.H. Holmgren.
The record derives from Tropicos which reports it as a synonym (record 50079702) with original publication details: Amer. Midl. Naturalist 33(1): 158 158 1945.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:187751-2.