Perennial from a short caudex; stem 1.5-15 dm, often spreading- hairy below, sometimes becoming stellate-puberulent above; lvs stellate-puberulent to subglabrous, and often long-hairy beneath, the basal and lowermost cauline ones small and soon deciduous; the others (except for the strongly reduced upper ones), mostly rather numerous, nearly alike in size and shape, sessile and tending to be broadly rounded and somewhat clasping at base, elliptic to ovate, lanceolate, or oblong, 3-12 cm נ7-40 mm, 2-5 times as long as wide, usually with a few irregularly spaced sharp teeth; infl loosely corymbiform to often umbelliform, at least in part, or the heads occasionally solitary; peduncles stellate-puberulent, occasionally with some longer hairs as well; invol 6-13 mm, its bracts imbricate in several series, glabrous or obscurely puberulent, occasionally with a few longer hairs, gradually tapering to a narrow but obtuse or rounded tip; achenes truncate, 2.5-3.5 mm; 2n=27. Woods, beaches, and fields, especially in sandy soil; Nf. and Lab. to N.J., w. through Man. and Io. to B.C. and Oreg. July-Sept. Var. fasciculatum (Pursh) LePage, ranging from Que. to Minn., s. to N.J., O., Ill., and Mo., is robust, 5-15 dm, with 25-50 rather firm lvs that seldom have any long hairs; the infl tends to be umbelliform, with stiff peduncles 2-4 cm. Var. kalmii, ranging from Me. and N.H. to Nf., Mich., Io., Oreg., and B.C., is more slender, 1.5-10 dm, with 5-30 rather thinner lvs that often have some long hairs beneath, the infl more open, with laxer peduncles to 10 cm (or the heads even solitary). (H. canadense)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.