About 125, incluing: Oenothera acaulis Oenothera albicaulis Oenothera argillicola Oenothera biennis Oenothera brachycarpa Oenothera caespitosa Oenothera californica Oenothera coronopifolia Oenothera coryi Oenothera deltoides Oenothera drummondii Oenothera elata Oenothera erythrosepala Oenothera flava Oenothera fruticosa Oenothera glazioviana Oenothera hookeri Oenothera jamesii Oenothera kunthiana Oenothera laciniata Oenothera longissima Oenothera macrocarpa Oenothera missouriensis Oenothera nuttallii Oenothera odorata Oenothera pallida Oenothera perennis Oenothera pilosella Oenothera primiveris Oenothera rhombipetala Oenothera rosea Oenothera speciosa Oenothera stubbei Oenothera taraxacoides Oenothera tetraptera Oenothera triloba