ABSTRACT
Distributions of Ohio’s native buckeye species, <em>Aesculus glabra</em> (Ohio buckeye) and <em>A. octandra</em> (yellow buckeye), were documented by collections from all parts of the state. <em>A. glabra</em> is associated with the Wisconsin and Illinoian drifts, and is restricted to outwash deposits and limestone bedrock areas beyond the limits of glaciation. <em>A. octandra</em> is confined to a part of the Unglaciated Allegheny Plateau, and to a westward extension across the state in the deeply dissected terrain bordering the Ohio River. The distribution of <em>A. glabra</em> is correlated with calcareous soils, and the distribution of <em>A. octandra</em> is inferred to be under the combined controls of topography and climates. Distribution maps, based on field records, are presented for the species in Ohio.