The differences in my leaves to those in the paper bugged me. So I contacted Dan Peppe PhD the co author of the paper you referenced. Believing he would have more insight and information for IDing these leaves. I am happy to say he answered my email. He sent me a Paper
REPRODUCTIVE AND VEGETATIVE ORGANS OF BROWNIEA GEN. N. (NYSSACEAE)
FROM THE PALEOCENE OF NORTH AMERICA
Steven R. Manchester1 and Leo J. Hickey
Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800, U.S.A.; and
Peabody Museum of Natural History, Yale University, New Haven, Connecticut 06520, U.S.A.
These fossil leaves more closely match the Browniea Gen .
Between your help and Peppe’s these leaves are now identified.
David C Powers