Salix sp. leaf from the Green River formation

This long, narrow leaf is most likely from a member of the Willow family, Salix sp. and comes from the Parachute Creek member of the Green River formation (Eocene, Lutetian stage).  It was found in Bonanza, Utah and I purchased it because it came with an ID. I am hoping that I can use this and other identified specimens that I purchase to help ID fossils that I have found in the field. There are not many resources easily accessible that show pictures and names for plant and insect fossils from the Green River formation.  I know I have found other examples of Salix sp. that are larger and more recognizable than this specimen but I need to go through my findings and locate it.