Taprooted; stem 0.7-3 m, essentially glabrous, nearly naked, its lvs, except those near the base, few and reduced to mere large bracts; principal lvs large, long-petiolate, the blade narrowly to broadly ovate, oblong, or elliptic, usually cordate (seldom only subtruncate) at the base, 1-5 נ0.7-3 dm, usually sharply toothed, glabrous or scabrous, sometimes hirsute on the midrib beneath; heads several or rather numerous in an open-corymbiform infl, relatively large, with ca 13 to ca 21 rays 2-3 cm, the disk 1.5-3.5 cm wide; invol 13-25 mm, its bracts essentially glabrous, strongly imbricate, the outer broadly elliptic, the inner elongate, more oblong, loose and broad- tipped; 2n=14. Prairies; s. Ont. and O. to Minn., s. to Ga. and Miss. July-Sept. (S. rumicifolium)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.