Silphium asteriscus var. asteriscus
Plants 40–150 cm. Leaves: basal caducous; cauline opposite or alternate; faces hirsute, hispid, or scabrous. Paleae puberulent to scabrous. Ray-florets 8–20. Disc-florets 35–110.2n = 14.
Phenology: Flowering summer–early fall.
Habitat: Prairies, meadows, open forests, roadsides
Elevation: 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.
"broader" is not a number.