This variable species is widespread across North America (2n = 32, 34, 36); var. autumnale occurs in eastern states. Sterile hybrids with flexuosum (2n = 28) have been reported (Y), and may be confused with the closely related H. virginicum S.F. Blake (also 2n = 28). There are also horticultural cultivars that have been derived from hybrids with H. bigelovii Gray, a western species (for details see www.helenium.net). H. virginicum is known only from Va. and Mo. but should be searched for elsewhere (FNA 20, Y, W). It differs from autumnale in its oblanceolate basal blades, usually persistent to flowering (versus oblanceolate, obovate or spathulate, withering by flowering); its mid-stem leaves usually entire (versus usually dentate) and its upper leaves entire (versus entire or dentate); the pappus of disc flowers at least half as long as the tube, keel-less and abruptly long-awned (versus less than half, keeled and attenuate).