[4] The original type description of the new species by paleobotanist Edward W. Berry, based on a compression fossil leaf specimen, was published in 1929.

[1] Roland W. Brown (1937) corrected the type locality to the older Republic area strata,[6] but occasional confusion as to the species age still occurred: notably Daniel I. Axelrod (1966) in his paper on the Copper Basin flora of Nevada considered the age of S. hesperia as Oligocene.

[1] Working from specimens collected in the Republic, Washington area in the early 1980s, the species was redescribed in 1987 by Jack A. Wolfe and Wesley C.

However they reject the assignment to S. hesperia of the single known Sassafras species leaf from the Eocene Florissant formation.

the species appears to have been possibly evergreen, based on the notably thick leaf remains, thicker than the younger S. ashleyi and S. columbiana.