| Boraginaceae | |
Hackelia diffusa var. arida
| (Piper) R.L. Carr | Mem. New York Bot. Gard. 26(1): 190 | 1976 |
| Boraginaceae | |
Hackelia diffusa var. coerulescens
| (Rydb.) I.M. Johnst. | Contr. Gray Herb. 68: 48 | 1923 |
| Boraginaceae | |
Hackelia diffusa var. cottonii
| (Piper) R.L. Carr | Mem. New York Bot. Gard. 26(1): 192 | 1976 |
| Boraginaceae | |
Hackelia diffusa var. diffusa
| | | |