21a. Eupatorium rotundifolium Linnaeus var. ovatum (Bigelow) Torrey ex de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 178. 1836.
Eupatorium ovatum Bigelow, Fl. Boston. ed. 2, 296. 1824; E. pubescens Muehlenberg ex Willdenow
Leaf blades 3-nerved distal to bases, 30–70 × 30–60 mm, broadest near middles, bases broadly cuneate to cuneate, margins serrate. 2n = 20, 30.
Flowering Jul–Aug. Moist, low ground, roadsides, sandy soils; 10–200+ m; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ky., La., Md., Mass., Miss., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Va., W.Va.
Variety ovatum is an apomictic polyploid that may be a derivative of Eupatorium rotundifolium and E. sessilifolium. Morphologically, it is closer to E. rotundifolium than to E. sessilifolium; the name E. pubescens has priority at species rank.
