| Name | Penstemon cardwellii Howell |
| Authorship | Howell |
| Rank | Species |
| Placed in | Penstemon Schmidel |
| Citation | 1901 Fl. N.W. Amer. 1: 510 |
| Holdings | 17 Specimens held in the Harvard University Herbaria identified as Penstemon cardwellii Howell |
| Identification made in | [no date] (17) |