| Plantaginaceae | |
Penstemon laetus subsp. filiformis
| D.D. Keck | Univ. Calif. Publ. Bot. 16(11): 394 | 1932 |
| Plantaginaceae | |
Penstemon laetus var. filiformis
| (D.D. Keck) McMinn | Man. Calif. Shrubs 517–518 | 1939 |
| Plantaginaceae | |
Penstemon laetus subsp. laetus
| | | |
| Plantaginaceae | |
Penstemon laetus var. laetus
| | | |
| Plantaginaceae | |
Penstemon laetus subsp. leptosepalus
| (Greene ex A. Gray) D.D. Keck | Univ. Calif. Publ. Bot. 16(11): 393 | 1932 |
| Plantaginaceae | |
Penstemon laetus var. leptosepalus
| Greene ex A. Gray | Syn. Fl. N. Amer. (ed. 2) 2(1): 442 | 1886 |
| Plantaginaceae | |
Penstemon laetus subsp. roezlii
| (Regel) D.D. Keck | Univ. Calif. Publ. Bot. 16(11): 390 | 1932 |
| Plantaginaceae | |
Penstemon laetus var. roezlii
| (Regel) Jeps. | Man. Fl. Pl. Calif. 916 | 1925 |
| Plantaginaceae | |
Penstemon laetus subsp. sagittatus
| D.D. Keck | Univ. Calif. Publ. Bot. 16(11): 395–396, f. 12 | 1932 |
| Plantaginaceae | |
Penstemon laetus var. sagittatus
| (D.D. Keck) McMinn | Man. Calif. Shrubs 518 | 1939 |
| Plantaginaceae | ** |
Penstemon laetus subsp. typicus
| D.D. Keck | Univ. Calif. Publ. Bot. 16(11): 392 | 1932 |