Perennial 2-7 dm with well developed slender stolons or superficial rhizomes and generally a short caudex, lightly floccose-tomentose when young, generally soon glabrate; basal lvs narrowly obovate to orbicular, rounded at the tip, tapering or abruptly contracted to the petiolar base, crenate-serrate or sometimes (especially toward the base) more deeply cut, to 20 cm (petiole included) נ6 cm; cauline lvs conspicuously reduced, becoming sessile and generally pinnatifid; heads several or rather many, the disk 7-14 mm wide; invol 4-6 mm, conspicuously shorter than the disk, the bracts often purple-tipped; rays 5-10 mm (rarely wanting); achenes usually glabrous; 2n=44, ca 90. Rich woods and rocky outcrops, especially in calcareous situations; Vt. to Fla., w. to Kans. and Tex., commoner southward. Apr.-June. (S. rotundus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.