Malodorous annual or short-lived perennial, erect, to 1(-2) m, with ascending branches; lvs beset with minute yellow glands, the lower blades lanceolate to ovate, to 12 cm, acute, deeply sinuate-pinnatifid to merely serrate, cuneate at base, the upper progressively less toothed or entire; fls sessile in small glomerules that are disposed in slender, somewhat elongate spikes, these in turn forming terminal panicles; cal 5-lobed, not obviously glandular; styles 3-4; seeds horizontal or some of them erect, thick-lenticular, not margined, 0.6-1 mm wide, dark brown, shining; 2n=16, 32, 64. Native of tropical Amer., established as a weed in gardens, roadsides, and waste places n. to Me. and Wis.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.