Sundrops
(Oenothera fruticosa)

also listed as O.tetragona. This uncommon plant of prairies and open woodlans is superficially similar to O. biennis, evening primrose. This species blooms in the daytime, however. Smooth leaves are variable, from linear-lanceolate to ovate. Style is cross-shaped, typical of this genus. (Onagraceae)