Silphium pinnatifidum, the tansy rosinweed[2] or cutleaf prairie dock, is a species of flowering plant in the family Asteraceae.

It is native to the Southeastern United States where it is found in Alabama, Georgia, Kentucky, and Tennessee.

[4] Because of loss of its fire-dependent habitat, this species is uncommon and is considered vulnerable.

[1][5] Although most populations are distinct, intermediate populations have been reported between Silphium pinnatifidum and Silphium terebinthinaceum, and some botanists consider S. pinnatifidum only a variety of S. terebinthinaceum.

S. pinnatifidum was once thought to be a result of hybridization between Silphium terebinthinaceum and Silphium laciniatum, although molecular studies have indicated that S. pinnatifidum is too closely allied to S. terebinthinaceum for this to be the case.