Oenothera cespitosa

Oenothera cespitosa, known commonly as tufted evening-primrose or fragrant evening-primrose, is a perennial plant of the genus Oenothera native to western North America from the western edge of the Great Plains and all parts of the Intermountain West in a wide range of dry habitats. Its flowers are open at night and fade by the next day. The species is cultivated in gardens, particularly in its native range.