Aesculus hippocastanum

Aesculus hippocastanum, the horse chestnut, is a species of flowering plant in the maple, soapberry and lychee family Sapindaceae. It is a large, deciduous, synoecious (hermaphroditic-flowered) tree. It is also called horse-chestnut, European horsechestnut, buckeye, and conker tree. It is not to be confused with the Spanish chestnut, Castanea sativa, which is a tree in another family, Fagaceae. Aesculus hippocastanum is a large tree, growing to about tall with a domed crown of stout branches. On old trees, the outer branches are often pendulous with curled-up tips. The leaves are opposite and palmately compound, with 5–7 leaflets long, making the whole leaf up to across, with a petiole. The leaf scars left on twigs after the leaves have fallen have a distinctive horseshoe shape, complete with seven "nails". The flowers are usually white with a yellow to pink blotch at the base of the petals; they are produced in spring in erect panicles tall with about 20–50 flowers on each panicle. Its pollen is not poisonous for honey bees. Usually only 1–5 fruits develop on each panicle. The shell is a green, spiky capsule containing one (rarely two or three) nut-like seeds called conkers or horse-chestnuts. Each conker is in diameter, glossy nut-brown with a whitish scar at the base. The common name horse chestnut originates from the similarity of the leaves and fruits to sweet chestnuts, Castanea sativa (a tree in a different family, the Fagaceae), together with the alleged observation that the fruit or seeds could help panting or coughing horses. Although it is sometimes known as buckeye, for the resemblance of the seed to a deer's eye, the term buckeye is more commonly used for New World members of the genus Aesculus. The native distribution of Aesculus hippocastanum given by different sources varies. , Plants of the World Online considered it to be native to the Balkans (Albania, Bulgaria, Greece and former Yugoslavia), but also to Turkey and Turkmenistan.