Perennial herb 0.5–1.2 m high, rarely annual; stem single or several, glabrous, from thickened woody rootstock.. Leaves pinnatifid with 3–5 segments or bipinnatifid with few side lobes, 5–15 cm long, segments linear, 1–6 cm long, 0.5–2 mm wide, glabrous; petiole 0.5–7 cm long.. Capitula terminal and solitary; stalks of individual capitula to 12 cm long; involucre 8–10 mm long; outer phyllaries 6–8, green, linear, glabrous or sparsely pubescent, the inner phyllaries 8, oblong, glabrous but for the apex; paleae linear.. Ray florets golden yellow, neuter, 5–8, tube glabrous, rays 10–20x3–5 mm; disc florets yellow, 3.8–5 mm long, glabrous or sparsely puberulous.. Achenes dark brown or black, flat, 9–18 mm long, glabrous or pilose on margin, curved near the apex when fully mature; aristae 2(–3), to 4.3 mm long, retrorsely barbed.
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