Sida 21: 902. 2004.
Plants 60–200 cm. Stems usually purple-spotted, sometimes uniformly purple, usually solid, sometimes hollow near bases, glabrous proximally to densely puberulent throughout, glandular-puberulent distally. Leaves in (3s–)4s–5s(–6s); petioles 5–20 mm, glabrous or pubescent; blades pinnately veined, lance-elliptic to lanceolate or lance-ovate, mostly (6–)8–23(–30) × (1.5–)2–7(–9) cm, bases gradually or abruptly tapered, margins sharply serrate or doubly serrate, abaxial faces gland-dotted and densely pubescent to glabrate, adaxial faces sparingly hairy or glabrous. Heads in flat-topped, corymbiform arrays. Involucres often purplish, 6.5–9 × 3.5–7 mm. Phyllaries glabrous or densely pubescent. Florets (8–)9–20(–22); corollas purplish, 4.5–7.5 mm. Cypselae 3–5 mm. 2n = 20.
Alta., B.C., Man., N.B., N.S., Nfld. and Labr. (Nfld.), Ont., P.E.I., Que., Sask., Ariz., Colo., Conn., Idaho, Ill., Ind., Iowa, Kans., Maine, Mass., Mich., Minn., Mo., N.C., N.Dak., N.H., N.J., N.Mex., N.Y., Nebr., Ohio, Pa., S.Dak., Utah, Va., Vt., W.Va., Wash., Wis., Wyo.
Varieties 3 (3 in the flora).
Eutrochium maculatum has the widest geographic distribution and greatest morphologic variability among species in the genus. The three varieties recognized here show intergradation where the ranges overlap.
|1||Stems densely puberulent throughout; leaves densely pubescent on abaxial faces, relatively thick; mostly w of Mississippi River||Eutrochium maculatum var. bruneri|
|1||Stems glabrous proximally, puberulent among heads; leaves usually glabrate (seldom strongly puberulent) on abaxial faces, relatively thin; mostly e of Mississippi River||> 2|
|2||Distalmost whorls of leaves subtending heads equaling or surpassing arrays of heads; maritime Canada, adjacent New England to ne Minnesota, n Michigan, and s Ontario||Eutrochium maculatum var. foliosum|
|2||Distalmost whorls of leaves subtending heads not equaling arrays of heads; Newfoundland to sw Ontario, s to n and w New England, Pennsylvania, North Carolina, Ohio, Indiana, Illinois, and Iowa||Eutrochium maculatum var. maculatum|