Perennial 3-8 dm from a branched, rhizomatous caudex or creeping rhizome, often with stoloniform but coarse, leafy basal offshoots, lightly floccose-tomentose when young, soon essentially glabrous; basal lvs long-petiolate, some or all with ±strongly cordate blade, these generally broadly rounded distally, crenate, to 11 נ11 cm, mostly 0.75-1.5(-1.75) times as long as wide, often held at an angle to the petiole, parallel to the ground; cauline lvs conspicuously reduced and generally ±pinnatifid, becoming sessile upward; heads several or rather many, the disk 5-12 mm wide; invol 5-8 mm, its bracts often strongly purple-tipped; rays 6-13 mm; achenes glabrous; 2n=44, 66, ca 132. Moist woods and swampy places; Lab. to Minn., s. to N.C., n. Ga., and c. Ark.; Fla. Apr.-Aug. (S. gracilis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.