Plants 40–120(–170) cm. Stems usually purple-spotted, sometimes uniformly purple, solid, glabrous proximally, glandular-puberulent distally. Leaves mostly in 3s–4s; petioles 7–25 mm, glabrous; blades usually ± 3-nerved, rarely pinnately veined, deltate-ovate or ovate to lance-ovate, 5–16 × 2–8 cm, relatively thick and firm (often rugose), bases usually abruptly contracted to petioles, margins coarsely serrate, abaxial faces densely gland-dotted and sparingly hirsute (at least on midribs and main veins), adaxial faces scabrous, glabrescent. Heads usually in ± convex, sometimes flat-topped, corymbiform arrays. Involucres often purplish, 6.5–9 × 2.5–5 mm. Phyllaries glabrous or sparsely hairy. Florets (4–)5–9(–10); corollas usually dark purple, rarely pinkish or white, 4.5–7 mm. Cypselae 3–4.5 mm. 2n = 20.
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