The buckeye trees (Aesculus glabra) in the United States belong to the horse chestnut family and include species like the Ohio buckeye, the yellow buckeye and the California buckeye. The Ohio buckeye has the privilege of being Ohio's state tree, with the nut it produces represented by the Ohio State University's mascot. Buckeye trees are identifiable by some of their features, not the least of which is the nut that Ohio natives will carry in their pocket for good fortune, according to the Ohio Department of Natural Resources website.
Look at the size of the buckeye tree when trying to tell it apart from other specimens. An Ohio buckeye growing by itself in the open may reach 60 feet tall and have a 30-foot wide spread of branches. The yellow buckeye can be 90 feet tall, but smaller species of buckeyes that strain to attain 30 feet in height include the red buckeye and the painted buckeye.
Examine the leaves of the buckeye trees. The palmately compound leaflets, arranged in a semi-circle pattern at the end of a long stalk, are as long as 6 inches and up to 2.5 inches in width in the case of the painted buckeye, though size varies with other buckeyes. Most American buckeye species have five leaflets on each leaf, with yellow buckeye sometimes having seven.
Inspect the flowers that develop on the buckeyes in the spring. Ohio buckeye has bell-shaped blooms that possess four yellow-green petals and seven stamens. The flowers emerge before or with the leaves and grow in upright clusters at the end of branches, says the National Audubon Field Guide to Trees. Red buckeye has reddish flowers growing in clusters, while the California buckeye of the West Coast has whitish to dull red flowers growing on 5- to 10-inch long stalks.
Study the buckeye nuts. Ohio buckeye nuts have a brown husk with spines and will break open when the nut is ripe. The nut gives the species its name as it supposedly looks like the shiny eye of a deer. The poisonous buckeye nut is an inch or two wide and a deep brown color. The nuts of the buckeye trees mature by the beginning weeks of fall.