Aesculus glabra is most commonly known as the Ohio buckeye, but also goes by the names of American buckeye and fetid buckeye. As the common names suggest, it’s native to North America, significant to Ohio, and emits unpleasant odors!
The Ohio buckeye grows mostly in the central-eastern United States, but reaches Canada (Ontario) at its northern range limit. These mid-sized trees are typically around 15m (50 ft.) tall with age. Typical of the genus Aesculus, the leaves are large and arranged as palmately-compound leaflets. As shown in the photograph, the fruits are spherical capsules with a leathery husk. These contain glossy brown seeds. Probably its most noteworthy characteristic is that all of its parts are considered highly toxic if ingested, due to chemicals such as glycoside aesculin and saponin aescin (USDA (PDF)). Fetid odors are released by the plant when bruised or crushed; I imagine this reduces the appeal of tasting it, and thus lowers the chances of one being inadvertently poisoned by sampling. Its soft light wood has workable properties that finds it used to build artificial limbs, but the species is ultimately of minimal commercial importance.
Aesculus consists of six species native to North America and at least seven native to Eurasia. The genus was named by Linnaeus after the Latin word for “edible acorns”, something seemingly unrelatable to species of Aesculus. The specific epithet signifies a smooth or glabrous surface, possibly referring to the leaves. Derivation of the common name is more obvious, referring to the pale scar on the seeds looking like a buck’s eye. This was originally coined by First Nations, who named the fruit “hetuck” meaning “eye of the buck. The term “buckeye” has cultural significance in Ohio, colloquially describing anyone from the state, and also being the official nickname for Ohio State University.
Ohio is also home to Aesculus flava (yellow buckeye), which is known to hybridize with the Ohio buckeye, though the two generally grow on different substrates. Distribution of Buckeyes (Aesculus) in Ohio notes that Ohio buckeyes grow predominantly on formerly glaciated land or glaciated outwash almost exclusively in calcareous soils, while the yellow buckeye occurs only in some regions on the Unglaciated Allegheny Plateau in southeastern Ohio.
In terms of its range in Canada, Aesculus glabra is believed to occur naturally only on Walpole Island in Ontario. Otherwise, populations are very small and possibly exist as the result of planted trees nearby. Located roughly 60km west and 80km north of the closest other Ohio buckeye populations, Walpole Island has long been occupied by First Nations. While the USDA considers it native to Ontario, an evaluation of this supposedly-natural growing Canadian population wasn’t able to determine if the trees growing on Walpole Island occurred naturally or were planted.