The northern limit of the distribution of Quercus imbricaria Michx. and Quercus palustris Muench, in the valley of the Iowa River is reached near Hills in Johnson County. Here and southward both species occupy the alluvial bottom lands, and before the extensive clearing of the alluvial forests they were freely intermingled. In view of this fact and of the well-known tendency of oaks to hybridize it is not surprising that forms which are evidently hybrids occur.
Proceedings of the Iowa Academy of Science
©1908 Iowa Academy of Science, Inc.
"A Hybrid Oak,"
Proceedings of the Iowa Academy of Science, 15(1), 77-83.
Available at: https://scholarworks.uni.edu/pias/vol15/iss1/11