Oenothera lamarckiana, commonly known as the evening primrose, is a flowering plant native to North America. It belongs to the family Onagraceae and is recognized for its bright yellow flowers that bloom in the evening. The plant typically grows in open fields and disturbed areas, reaching heights of up to 1.2 meters (4 feet). This species is notable for its role in genetics and evolution studies, particularly due to its rapid rate of mutation and adaptability. Oenothera lamarckiana has been used in research to understand the mechanisms of speciation and hybridization, making it a significant subject in the field of botany.