Undescribed Bitterwort
Green River Formation
Middle Eocene
Lincoln County, Wyoming

This fine example is interpreted to be an undescribed bitterwort leaf possible from the family Aristolochiaceae. This specimen is 13 cm and displays a complete stem. This is a interesting specimen of an unusual plant. Bitterworts (also known as pipevine or Dutchman's pipe) are perennial herbaceous plants, shrubs, and vines. There are about 400 living specie today. These plant leaves are rare in the Green River Formation. This specimen is from the 18 inch layer.