This native plant is a member of the evening primrose family and superficially the flowers look a bit like those of the common evening primrose. This species, though, has 4 wide sepals as long as the 4 petals. These are not reflexed (bent backwards). The ½ inch wide yellow flowers are on short stalks along the leaf stalk rather than at the end of the stem. The name "seedbox" refers to short, cubical pod fruit. The stem branches multiple times and is smooth. The leaves are lance-shaped, pointed and dark green. The plant grows 2-3 feet tall and is found is swampy or wet areas. It is locally common in southern Ontario and much of eastern United States. The blooming period is June to August. It is also called rattlebox.