Oenothera laciniata Hill
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual, simple or branched from the base, decumbent to erect, 1–4(–8) dm; lvs oblanceolate to oblong or lanceolate, 3–8 cm, tapering to the base, prominently sinuate-dentate to pinnatifid, green, sparsely puberulent to glabrous above; fls few, sessile in the axils of the scarcely reduced upper lvs, not forming a distinct spike; hypanthium hirsute, 1.5–3.5 cm; sep 6–12 mm, reflexed separately or connivent; pet 5–18 mm; fr linear, straight or curved, 1.5–3.5 cm; seeds thick-ellipsoid, pale brown, conspicuously pitted; 2n=14. Dry, usually sandy soil; Me. to S.D., s. to S. Amer. May–Oct. Our plants, as here described, are var. laciniata.