Sassafras hesperia

Sassafras hesperia is an extinct species of the Sassafras genus of the Lauraceae family. It lived in the Klondike Mountain Formation of Washington and British Colombia during the Eocene period.

Its original type description was made by Dr. Edward W. Berry by a compression fossil leaf specimen published in 1929. When first published, it was misidentified, saying it was found in the Latah Formation in Spokane, Washington. Rowland W. Brown corrected this, but confusion as to the age of the species still occured.

In 1987, the species was redescribed by Jack A. Wolfe and Wesley C. Wehr. Both of these men noted that is was one of the most common dicots in the Klondike Mountain Formation, that it occurs in Princeton and Joseph Creek floras, and in Thunder Mountain flora of similar age. However, they reject the assignment to S. hesperia of the single Sassafras species leaf from the Florissant formation. Wolfe and Wehr also noted that Oligocene Sassafras ashleyi is closely related.

The leaves are huge, with fossils over 5.3 inches. The species may have been evergreen, with leaf remains thicker than S. ashleyi and S. columbiana. This is different in modern day Sassafras which are deciduous.