Silphium pinnatifidum

Silphium pinnatifidum
Conservation status
Vulnerable  (NatureServe)[1]
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Asterales
Family:	Asteraceae
Tribe:	Heliantheae
Genus:	Silphium
Species:	S. pinnatifidum
Binomial name
Silphium pinnatifidum Elliott

Silphium pinnatifidum, the tansy rosinweed^[2] or cutleaf prairie dock, is a species of flowering plant in the Composite family. It is native to the Southeastern United States where it is found in Alabama, Georgia, Kentucky, and Tennessee.^[3] Its habitat is prairies and cedar glades, where it can be found in either wet or dry locations.

Note the large phyllaries often indicative of Silphium

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.^[4]

References