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. More or less divisible into 3 vars.:
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.