Apart from the horse chestnut which is the only Aesculus species native to Europe, there are twelve other species of Hipposcastanum that are found throughout the northern hemisphere, mainly in eastern Asia and eastern USA. There is also a single species native to western North America and another native to northwestern Mexico (Hardin, 1960).
Species of Hippocastanum
A. hippocastanum: Horse chestnut - Bulgaria, N. Greece, S. Albania
A. x carnea: Red horse chestnut
A. turbinata: Japanese horse chestnut - Japan
A. californica: Buckeye - California, United States
A. parryi: Parry buckeye - California, Mexico
A. flava: Sweet or yellow buckeye - South east United States
A. glabra: Ohio buckeye - South east United States
A. parvia: Red buckeye - South east United States
A. parviflora: Dwarf buckeye - South east United States
A. sylvatica: No common name - South east United States
A. assamica: No common name - N. Siam, NW Indo-China, s. China, NE Pakistan, Bhutan
A. indica: Indian horse chestnut - NW Himalayas
A. chinensis: Chinese horse chestnut - China
A. wilsonii: Wilson's horse chestnut - Central China
But which conker is the best for playing the game with? We will be conducting experiments over the coming months and will keep you updated with regard to the results.
Table compiled from: Bean (1925) and Forest et al. (2001).