Plants 40-150 cm. Leaves: basal caducous; cauline opposite or alternate; faces hirsute, hispid, or scabrous. Paleae puber-ulent to scabrous. Ray florets 8-20. Disc florets 35-110. 2n = 14. Flowering summer-early fall. Prairies, meadows, open forests, roadsides; 50-1000 m; Ala., Ark., Fla., Ga., Ky., La., Miss., Mo., N.C., Okla., S.C. Tenn., Tex., Va. The name Silphium asperrimum has been misapplied to S. radula. Based upon examination of a photograph of the type and of the original description, S. asperrimum should be synonymized with S. asteriscus.