Also called Cut-leaf Prairie Dock. This plant is closely related to Silphium terebinthinaceum and is often listed as a sub-species of it. The plant forms a taprooted clump of basal leaves that reach 2 foot tall. The leaves can be deeply lobed to almost dissected in appearance. Flowering stalks appear midsummer and are between 6 and 10 feet tall (usually trending toward the shorter) leafless with large sunflower-like flowers July-September. Preference is for full to part sun and very dry soil. In the wild it is typically found in cedar glades, barrens and dry prairie. Fairly rare. Hybridizes readily with S. terebinthinaceum. Zone 4-8. TN/KY ecotype.