Plants caulescent, 75-300 cm; fibrous rooted. Stems square, glabrous, hispid, or scabrous. Leaves: basal caducous; cauline usually opposite, rarely whorled (in 3s), petiolate or sessile; blades deltate, lanceolate, or ovate, 2-41 × 0.5-24 cm, bases attenuate or truncate (distal connate-perfoliate), margins entire, dentate, or bidentate, apices acuminate to acute, faces scabrous to hispid. Phyllaries 25-37 in 2-3 series, outer appressed, apices acute to acuminate, abaxial faces scabrous or hispid. Ray florets 17-35; corollas yellow. Disc florets 85-150 (-200); corollas yellow. Cypselae 8-12 × 5-9 mm; pappi 0.5-1.5 mm.