Erect, rhizomatous perennial herb. Stems usually glabrous, sometimes sparsely clothed in short hairs, up to 2-(3) m tall. Lower and mid cauline lvs usually glabrous, sometimes moderately clothed in short hairs on lower surface and sparsely hairy on upper surface, petiolate, ovate-triangular, 2-pinnatisect, or 3-foliolate and leaflets 1-pinnatisect; segments ± entire to coarsely and irregularly serrate, (2)-4-16 cm long. Upper cauline lvs similar to lower but becoming shortly petiolate or apetiolate, smaller, and often 3-lobed or not lobed. Capitula c. 8-12 cm diam., in loose cymes. Involucral bracts in 1 row, glabrous, or ciliate to moderately hairy, narrow-lanceolate, subulate, or elliptic and narrowed to base, 8-20 × 3-5 mm. Receptacular scales membranous, with apices densely covered in short hairs. Ray florets 8-numerous, yellow; disc florets numerous, greenish yellow. Achenes brown, glabrous, 3.5-5 mm long; corona indistinct.