Oenothera biennis L.

• Authority

  Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

• Family

  Onagraceae

• Scientific Name

  Oenothera biennis L.

• Description

  Species Description - Biennial or short-lived perennial, 0.5–2 m; lvs lanceolate to oblong, mostly 1–2 dm, acute or acuminate, entire to repand-dentate, often crisped on the margin, sessile or short-petioled, glabrous to canescent, fls in stiff, terminal, simple or branched, ± leafy-bracteate spikes; hypanthium 2–5 cm; sep 1–3 cm, their appendages terminal, 1–5 mm, connivent for most of their length before anthesis; pet yellow, 1–2.5 cm; anthers 4–7 mm; fr 1.5–4 cm, stout, tapering upwards; seeds 1.2–1.8 mm, angular-prismatic; 2n=14, a complex heterozygote. Fields, roadsides, prairies, and waste places, throughout most of the U.S. and s. Can. July–Sept.

• Common Names

  common evening-primrose