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