This is a photo of a white walnut and a black walnut which are growing very close to each other in a very interesting small sandy, open creek bottom along Barren Creek in the Shawnee National Forest in South Pope County, Illinois. White Walnuts, or Butternuts, are declining badly across their range as the result of a blight. In this photo you can see how the two nuts are clearly distinguishable. Ironically, the darker, oval nut is the Butternut, while the lighter, round nut is the Black Walnut. Both trees are native to the Eastern U.S. and look similar, with the white walnut having a lighter bark.