Silphium radula

Plants caulescent, 30-250 cm; fibrous rooted. Stems terete, scabrous, hispid, or hirsute. Leaves: basal persistent or caducous, petiolate; cauline alternate or opposite, petiolate or sessile; blades lanceolate to ovate, 2-22 × 0.5-8 cm, bases attenuate to round, margins coarsely dentate or entire, apices acuminate to acute, faces scabrous, hispid, or hirsute. Phyllaries 18-37 in 2-4 series, outer appressed or reflexed, apices acute, abaxial faces scabrous. Ray florets 12-30+; corollas yellow. Disc florets 100-175; corollas yellow. Cypselae 10-17 × 7-15 mm; pappi 2-5 mm.