In studying the distribution of the native forest-trees of Nebraska, I have evidence that most of them have migrated up the Missouri River and westward from it up the rivers which empty into it from the westerly side. A few species have come down from the Rocky Mountains and migrated eastward for greater or less distances.
Proceedings of the Iowa Academy of Science
©1906 Iowa Academy of Science, Inc.
Bessey, Charles E.
"The Forest Trees of Eastern Nebraska,"
Proceedings of the Iowa Academy of Science, 13(1), 75-87.
Available at: https://scholarworks.uni.edu/pias/vol13/iss1/13