Common Evening Primrose
Oenothera biennis /Evening Primrose Family
The pretty yellow flowers on this plant wilt by early afternoon, so they have to be seen early in the day. The large X-shaped structure is the pistil. These plants come up from seed the first year and bloom the second year, making them biennials.
Where seen: Oak Ridge, Cherokee National Forest, Great Smoky Mountain NP, Warriors' Path SP