Thanks Yvonne.Oenothera biennis
The mature seeds contain approximately 7–10% gamma-linolenic acid (GLA), an essential fatty acid. Evening primrose oil (EPO), containing GLA, is often used to treat some medical conditions, and is considered a dietary supplement rather than a drug.
The plant's leaves are edible and traditionally were used as a leaf vegetable. The roots are also edible.
(From Wiki)