Buckeyes are the seeds produced by trees belonging to the genus Aesculus, which are native to the temperate regions of the Northern Hemisphere. These seeds are commonly referred to as buckeyes in North America and horse-chestnuts in Europe. The name “buckeye” comes from the seed’s appearance, which is a rich, shiny brown with a pale spot, resembling the eye of a male deer. All parts of these trees, including the seeds, contain compounds that are toxic to humans and many animals.
Identifying the Buckeye Tree Genus
Trees in the Aesculus genus possess distinct morphological features for identification. A primary characteristic is the palmately compound leaf structure, where five to seven leaflets radiate outward from a central point, much like the fingers from a hand. These leaflets are oppositely arranged on the branch.
The bark of a mature buckeye tree ranges from light gray to reddish-brown, starting smooth on younger specimens and becoming rougher and scaly with age. The fruit capsule houses the buckeye seed; this round, leathery husk can be smooth, warty, or slightly spiny, depending on the species.
As the fruit matures in the fall, the exterior husk splits open into three sections to release the one to three seeds. Each seed features a pale scar called the hilum, which marks where the seed was attached inside the capsule.
Common Species of Buckeye Trees
The Ohio Buckeye (Aesculus glabra) is a common North American variety, often reaching heights between 30 and 60 feet across the Midwestern and Great Plains states. Its yellowish-green flowers appear in erect, showy clusters, distinguished by stamens that extend beyond the petals. The fruit capsule of the Ohio Buckeye is usually spiny or warty on the exterior.
The Yellow Buckeye (Aesculus flava), native to the Appalachian Mountains, is the largest North American buckeye, sometimes exceeding 80 feet in height. Unlike the Ohio Buckeye, the Yellow Buckeye produces smooth fruit capsules. The yellow flowers of this species have stamens that are shorter and contained within the petals.
The California Buckeye (Aesculus californica) is found along the West Coast. This species is adapted to the dry summers of its native habitat by shedding its leaves early. The California Buckeye features fragrant, showy flowers that are typically white to pale pink. Other species like the Red Buckeye (Aesculus pavia) demonstrate the variation within the genus.
Toxicity and Safe Handling
The seeds and all other parts of buckeye trees are not safe for consumption because they contain toxic compounds. The primary poisonous agents are neurotoxic saponins and glycosides, such as aesculin and aescin, which affect the nervous system and gastrointestinal tract. Ingestion of any part of the buckeye plant can lead to significant illness in both humans and livestock.
It is important not to confuse the buckeye seed with the edible chestnut, which belongs to an entirely different genus, Castanea. Common symptoms of buckeye poisoning include severe digestive upset, such as nausea, vomiting, and diarrhea. More serious effects can involve muscle weakness, loss of coordination, dilated pupils, and in severe cases, paralysis or coma. Buckeye seeds should never be eaten or prepared for consumption.