four-point evening-primrose, more...
[Oenothera heterophylla var. rhombipetala Spach, more]
Etymology: Oenothera: from Greek oinos, "wine," and thera, "to imbibe," because an allied European plant was thought to induce a taste for wine
Plants: erect, biennial, 16"-40" tall forb
Leaves: linear to lance-like, alternate
Flowers: yellow, 4-parted, 1/3"-1 1/4" wide, petals elliptical to oval; inflorescence a 3"-12" dense, terminal spike; blooms June-Sept.
Fruits: mostly linear, usually curving capsule; seeds without tufts of hair at the top,
Habitat: fields, prairies; in sandy soil