Southern sundrops

This is some species of Oenothera. Depending on what time of day you saw this blooming it is probably either sundrops (O. fruticosa), which blooms in the day, or common evening primrose (O. biennis), which partially closes its flowers during the day. What little I can see of the leaves makes me think it's O. fruticosa. The four radially symmetrical petals and cross-shaped stigma are typical of family Onagraceae.