Evening Primrose is a biennial weed but more likely a wildflower. It has 4 yellow petals and the seed pod is quite distinctive. It is one-eighth inch round and 1-2 inches long.

Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension

Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension

Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension