| Megapterium canescens | Oenothera canescens Torr. & Frém. sect. Gauropsis |
| Megapterium dissectum | Oenothera dissecta A.Gray ex S.Watson sect. Leucocoryne |
| Megapterium fremontii | Oenothera fremontii S.Watson sect. Megapterium |
| Megapterium macrocarpum | Oenothera macrocarpa Nutt. sect. Megapterium |
| Megapterium oklahomense | Oenothera oklahomensis (Norton) Hitchc. sect. Megapterium |