Caulescent annual or biennial 2-10 dm, commonly minutely hirtellous-puberulent under the heads, otherwise generally glabrous or nearly so; lvs entire to pinnatisect, the basal sometimes much the largest and persistent, to 25 נ6 cm, sometimes deciduous and scarcely larger than the well developed cauline ones; heads several or occasionally solitary; invol 1-2 cm at anthesis; body of the achene 4-5 mm, the filiform, subapically very fragile beak longer, often twice as long; 2n=12. Fields, dry woods, bottomlands, and waste places; Del. and Md. to Ill. and Kans., s. to Fla. and Tex. June-Sept. (Sitilias c.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.