Coarse, aromatic perennial 4-15 dm from a stout rhizome, glabrous or nearly so; lvs numerous, 1-2 dm, nearly half as wide, sessile or short-petiolate, punctate, pinnatifid with evidently winged rachis, the pinnae again pinnatifid or deeply lobed, with broadly winged rachis, the pinnules often again toothed; heads disciform, numerous, commonly 20-200, the disk 5-10 mm wide; 2n=18. Roadsides, fields, and waste places; native of the Old World, established throughout most of the U.S. and adj. Can. Aug.-Oct.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
This is a medicinal plant which has been cultivated in gardens since pioneer times. It has escaped in all parts of the state. Apparently it propagates entirely by underground stems since it is found so sparingly and about the site of a former habitation.
Indiana Coefficient of Conservatism: C = null, non-native