Eocene Green River Winged Seed P-PCM-16-069

Ailanthus confucii Seed
Green River Formation
Middle Eocene
Lincoln County, Wyoming

Here is a good example of the winged seed of Ailanthus which is a close relative of the Tree of Heaven.  The seed core is visible and the venation in the seed wings is weak.  The seed is over 3 cm long.  It was collected from the 18 inch layer.
Ailanthus is a member of Sapindales family that includes Sumac, Astronium, Soapberry and Tree of Heaven.  A. confucii has a very characteristic winged seed shape.  Today Ailanthus is survived by ten living species and the genus is native only to Asia, Australia, and New Guinea.  Although found in the Green River Formation it eventually became extinct in North America.