The glossy, dark brown objects found beneath buckeye trees often spark curiosity due to their resemblance to edible chestnuts. This polished appearance, marked by a pale, round scar, is what gives the object its common name, a reference to the eye of a male deer, or “buck’s eye.”
Botanical Classification of the Buckeye
The object commonly called a buckeye “nut” is, in botanical terms, a seed, not a true nut. It is the seed of trees belonging to the genus Aesculus, such as the Ohio Buckeye (Aesculus glabra), which are part of the soapberry family.
A true nut, as defined by botanists, is a specific type of dry, single-seeded fruit that develops from a compound ovary and possesses a hard, woody shell. This shell, or pericarp, does not split open at maturity to release the seed. Examples of true nuts include the acorn, hazelnut, and chestnut.
The buckeye’s casing is a leathery, often spiny husk that naturally splits into three parts to disperse the seeds inside. The buckeye is accurately described as a large, inedible seed contained within a capsule fruit.
Toxicity and Safety Concerns
Regardless of its botanical classification, the buckeye seed carries significant public safety concerns because it is poisonous to humans and many animals. Every part of the tree, including the leaves, bark, and especially the seeds, contains toxic compounds. The primary toxic principles are a group of glycosides and saponins, which include aesculin, and a narcotic alkaloid.
Ingestion of any part of the buckeye can lead to severe illness, affecting both the gastrointestinal and nervous systems. Symptoms of poisoning typically include vomiting, diarrhea, and a staggering gait. More serious reactions can involve muscle twitching, severe trembling, and in rare cases, paralysis or coma.
Accidental ingestion remains a danger, particularly for small children and pets, as dogs are especially susceptible to poisoning. Though the seeds have a sweet beginning taste that quickly turns bitter, limiting large-scale consumption, immediate medical or veterinary attention is strongly recommended if any part of a buckeye is consumed.
Identifying the Buckeye Tree
The buckeye seed originates from a medium-sized deciduous tree native to North America, most famously the Ohio Buckeye. The tree can be identified by its distinctive foliage, which is arranged oppositely on the branches. Each leaf is palmately compound, meaning it resembles an open hand with five to seven leaflets radiating from a central point.
The bark on mature trees is typically a light gray and becomes furrowed, breaking into scaly, somewhat platy sections. In the spring, the tree produces showy, upright clusters of greenish-yellow flowers that attract pollinators.
The fruit capsule, which houses the seed, is light brown and roughened by blunt spines or warts before it splits open in the fall. The common Ohio Buckeye is often confused with the related European Horse Chestnut (Aesculus hippocastanum), which is also in the Aesculus genus and bears similar seeds. While both are toxic, the Horse Chestnut generally has seven larger leaflets and a fruit capsule covered in sharper spines.