"Stems 6–20 dm, glabrous or nearly so below the infl, slightly glaucous, usually purple only or chiefly at the nodes, otherwise greenish, usually solid, the pith remaining intact or ultimately developing a slender central cavity; lvs mostly in 3’s or 4’s, lanceolate to ovate or elliptic, 8–30 × 2.5–15 cm, gradually or sometimes rather abruptly narrowed to the short petiole, pinnately veined, usually sharply toothed, the lower surface glabrous or sparsely and inconspicuously short-hairy; infl convex; invol imbricate, 6.5–9 mm, its bracts well imbricate, commonly 3-nerved, obtuse or acutish; fls 4–7 per head, generally very pale pinkish or purplish, but variable; 2n=20, 40. Thickets and open woods, often in drier habitats than related spp.; s. N.H. to Va. and in the mts. to Ga., w. to Wis., Io., Okla., and w. Fla. July–Sept. (E. trifoliatum.) Plants from our western border, as in Minn., Io., and Mo., have the lvs more evidently short-hairy across the surface beneath, and have been distinguished as var. holzingeri (Rydb.) E. E. Lamont."