Buckeye
(This article is about the plants called buckeyes. There is also a place called Buckeye, Arizona in the United States of America. A buckeye is also a breed of chicken, see buckeye (chicken). The American State of Ohio is popularly called the Buckeye State).
| Buckeyes and Horse-chestnuts | ||||||||||||
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 Common Horse-chestnut Aesculus hippocastanum | ||||||||||||
| Scientific classification | ||||||||||||
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| Species | ||||||||||||
| Aesculus arguta: Texas Buckeye Aesculus buckleyi Aesculus californica: California Buckeye Aesculus chinensis: Chinese Horse-chestnut Aesculus flava (A. octandra): Yellow Buckeye Aesculus glabra: Ohio Buckeye Aesculus hippocastanum: Common Horse-chestnut Aesculus indicum: Indian Horse-chestnut Aesculus neglecta: Dwarf Buckeye Aesculus parviflora: Bottlebrush Buckeye Aesculus pavia: Red Buckeye Aesculus sylvatica: Painted Buckeye Aesculus turbinata: Japanese Horse-chestnut |
Buckeye and Horse-chestnut are the names given to trees and shrubs of the genus Aesculus. They have traditionally been treated in the horse-chestnut family Hippocastanaceae, but genetic evidence shows that this family, along with the maples (Aceraceae), are probably better included in the soapberry family (Sapindaceae), as the differences between the three groups are small and of doubtful significance. The Common Horse-chestnut, Aesculus hippocastanum, was formerly placed in the segregate genus Hippocastanum.
They are woody plants from 4 to 35 m tall (depending on species), and have stout shoots with resinous, often sticky, buds; opposite, palmately divided leaves, often very large (to 65cm across in the Japanese Horse-chestnut Aesculus turbinata); and showy insect-pollinated flowers, with a single five-lobed petal (actually five petals fused at the base). The fruit is a rich glossy brown to blackish-brown nut, usually globose with one nut in a green or brown husk, but sometimes two nuts together in one husk, in which case the nuts are flat on one side; the point of attachment of the nut in the husk shows as a large circular whitish scar.
The most familiar member of the genus worldwide is the Common Horse-chestnut Aesculus hippocastanum, native to a small area of the Balkans in southeast Europe, but widely cultivated for its spectacular spring flowers (see photo, below). The Yellow Buckeye Aesculus flava (syn. A. octandra) is also a valuable ornamental tree with yellow flowers, but is less widely planted. Among the smaller species, the Bottlebrush Buckeye Aesculus parviflora also makes a very interesting and unusual flowering shrub. Several other members of the genus are used as ornamentals, and several horticultural hybrids have also been developed.
They are generally fairly problem-free, though a recently discovered leaf-mining moth Cameraria ohridella is currently causing major problems in much of Europe, causing premature leaf fall which looks very unattractive. The symptoms (brown blotches on the leaves) can be confused with damage caused by the leaf fungus Guignardia aesculi, which is also very common but usually less serious.
Buckeyes are poisonous, but some native American tribes leached the pulverized nuts to make them edible. Crushed buckeye nuts have also been used, thrown into lakes by poachers, to kill fish for easy capture. California Buckeyes Aesculus californica are known to cause poisoning of honeybees from toxic nectar (other locally native bee species not being affected). Other buckeye species are thought to have the same effect, but the toxins are diluted because the tree is not so predominant in any one area. In Britain, the nuts of Aesculus hippocastanum are used for the popular children's game conkers. The wood is fairly soft and little-used.
The Ohio buckeye Aesculus glabra is the state tree of Ohio and an original term of endearment for the pioneers on the Ohio frontier, with specific association with William Henry Harrison. Subsequently, the use of the term for the Ohio State University sports teams made the term a widely known title for any graduate, or indeed, any Ohioan. Ironically, the world-record Ohio Buckeye tree is located in Kentucky, not Ohio, and as a consequence, there has for some time been a reward offered for anyone who discovers an Ohio Buckeye in Ohio large enough to become the new champion. Of small but interesting note is the Buckeye confection, which is made by encasing a dollop of peanut butter with milk chocolate. These can be found throughout Ohio, especially as a treat during Christmas time.
Aesculus hippocastanum