⚠ Version 1 of The Plant List has been superseded.
This name is in version 1.1 of The Plant List, record tro-29201391, with some changes.
This name is a synonym of Penstemon watsonii subsp. laxus (A. Nelson) D.D. Keck.
The record derives from Tropicos which reports it as a synonym (record 29201391) with original publication details: Bot. Gaz. 54(2): 147 147 1912.
Full publication details for this name can be found in IPNI: urn:lsid:ipni.org:names:187597-2.