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{{Taxobox
| color = lightgreen
| name = ''Aesculus'' - Buckeyes and Horse-chestnuts
| image = Horse-chestnut 800.jpg
| image_width = 300px
| image_caption = ''Aesculus hippocastanum''
| regnum = [[Plant]]ae
| divisio = [[flowering plant|Magnoliophyta]]
| classis = [[dicotyledon|Magnoliopsida]]
| ordo = [[Sapindales]]
| familia = [[Sapindaceae]]
| genus = '''''Aesculus'''''
| genus_authority = [[Carolus Linnaeus|L.]]
| subdivision_ranks = Species
| subdivision =
''[[Aesculus arguta]]'': Texas Buckeye<br/>
''[[Aesculus californica]]'': California Buckeye<br/>
''[[Aesculus chinensis]]'': Chinese Horse-chestnut<br/>
''[[Aesculus flava]]'' (''A. octandra''): Yellow Buckeye<br/>
''[[Aesculus glabra]]'': Ohio Buckeye<br/>
''[[Aesculus hippocastanum]]'': Common Horse-chestnut<br/>
''[[Aesculus indica]]'': Indian Horse-chestnut<br/>
''[[Aesculus neglecta]]'': Dwarf Buckeye<br/>
''[[Aesculus parviflora]]'': Bottlebrush Buckeye<br/>
''[[Aesculus pavia]]'': Red Buckeye<br/>
''[[Aesculus sylvatica]]'': Painted Buckeye<br/>
''[[Aesculus turbinata]]'': Japanese Horse-chestnut<br/>
''[[Aesculus wilsonii]]'': Wilson's Horse-chestnut
}}
The genus '''''Aesculus''''' comprises 20–25 species of [[deciduous]] [[tree]]s and [[shrub]]s native to the temperate [[northern hemisphere]], with 7–10 species native to [[North America]] and 13–15 species native in [[Eurasia]]; there are also several natural [[hybrid]]s. They have traditionally been treated in their own usually monogeneric family [[Hippocastanaceae]], but genetic evidence has lead to this family, along with the [[Aceraceae]] ([[Maple]]s and ''[[Dipteronia]]''), being included in the soapberry family ([[Sapindaceae]]).
The North American species are known as '''Buckeyes''' and the Eurasian species as '''Horse-chestnuts'''. Some are also called "White Chestnut" or "Red Chestnut" (as in some of the [[Bach flower remedies]]. In Britain, they are sometimes called "Conker trees" because of their link with the game of [[Conkers]] ).
== Etymology ==
The name Horse-chestnut, hyphenated here to avoid confusion with the true [[chestnut]]s (''Castanea'', [[Fagaceae]]), is also often given as "Horse Chestnut" or "Horsechestnut". One species very popular in cultivation, the Common Horse-chestnut ''Aesculus hippocastanum'' is also often known as just "Horse-chestnut". Linnaeus named the genus ''Aesculus'' after the Roman name for an edible acorn. The use of the term "horse" refers to their strength or inedibility, the word "horse" originally meant strong or powerful, and does not here refer to their fitness as fodder for horses, except in folk etymology. The name buckeye derives from the resemblance of the seed to the brown eye of a buck (male [[deer]]), and horse-chestnut from the external resemblance of the seed to a chestnut, but being inedible. The Buckeye blooms in summer and the Horse-chestnut in late spring.
== Description ==
''Aesculus'' are [[woody plant]]s 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 65 cm across in the Japanese Horse-chestnut ''Aesculus turbinata''); and showy insect-pollinated [[flower]]s, with a single four- or five-lobed petal (actually four or five petals fused at the base). Flowering starts after 80–110 [[growing degree day]]s. The fruit is a rich glossy brown to blackish-brown [[Nut (fruit)|nut]] 2–5 cm diameter, 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 husk has scattered soft spines in some species, spineless in others, and splits into three sections to release the nut.
== Cultivation ==
[[Image:Aesculus carnea BotGartenMuenster PurpurKastanie 6685.jpg|thumb|left|240px|Flower of the Red Horse-chestnut (''Aesculus x carnea'')]]
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 throughout the temperate world. 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, most notably the Red Horse-chestnut ''A. x carnea'', a hybrid between ''A. hippocastanum'' and ''A. pavia''.
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. Common Horse-chestnut is also used as a food plant by [[Sycamore (moth)|The Sycamore]], another species of moth.
Another disease in parts of North West Europe and North America is [[Bleeding canker]] [http://www.forestresearch.gov.uk/bleedingcanker].
==Uses==
The nuts contain high concentrations of a [[saponin]]-class toxin called [[Aesculin]], which is toxic to many animals including humans because it causes [[hemolysis]] (destruction of [[red blood cell]]s). The saponin can be eliminated by leaching the pulverized nuts in multiple changes of boiling water, to yield a wholesome [[starch]]y [[porridge]] once important to some [[Indigenous peoples of the Americas|Native American]] tribes. Some animals, notably [[deer]] and [[squirrel]]s, are resistant to the toxins and can eat the nuts directly. An interesting side-note is that Aesculin is a natural [[pH indicator]] which, when extracted turns from colourless to fluorescent blue under [[UV light]] in an acidic [[pH]] range.
Crushed buckeye nuts have also been thrown into [[lake]]s by [[poaching|poachers]], to kill fish for easy capture.
California Buckeyes ''[[Aesculus californica]]'' are known to cause poisoning of [[honeybee]]s 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 trees are not usually abundant enough in any one area.
The wood is very pale whitish-brown, fairly soft and little-used. Uses include cheap furniture, boxes and firewood.
In several European countries a new disease has been found in several species of ''Aesculus''. For more information check http://www.kastanjeziekte.wur.nl (in Dutch).
In [[United Kingdom|Britain]] and [[Ireland]] the game of [[conkers]] remains a common childhood pastime.
In some cultures, the buckeye tree is thought to bring good luck.[http://www.ohiodnr.com/forestry/education/buckeyetrees2.htm][http://www.biosci.ohio-state.edu/~herb/buckeye.htm]
The [[Mexican Buckeye]] is related to ''Aesculus'', but is in a separate genus, ''Ungnadia''.
===Uses in homeopathic medicine===
Aesculus is used in homeopathic medicine for pain in the sacroiliac region and rectal pain <ref>{{cite book
| last = Morrsion, MD
| first = Roger
| title = Desktop guide to keynotes and comfirmatory symptoms
| publisher =Hahnemann Clinic Publishing
| date = 1993
| location =Grass Valley, CA
| ISBN =0-9635368-0-X}}
</ref>.
== References ==
{{reflist}}
<gallery>
Image:AesculusChinensis.jpg|Chinese Horse-chestnut (''Aesculus chinensis'') young leaves in spring ...
Image:AesculusChinensisLeaf.jpg|... and fully grown, in summer
Image:Aesculus californica.jpg|California Buckeye (''[[Aesculus californica]]'') leaves
Image:Paardekastanje wit uitgelopen knop.jpg|''Aesculus hippocastanum'' bud opening in spring
Image:Horse Chestnut Tree.jpg|[[Common Horse-chestnut]] tree in winter
Image:Kiev kashtan.jpg|[[Common Horse-chestnut]] tree
Image:Aesculus carnea BotGartenMuenster PurpurKastanie 6685.jpg|Red Horse-chestnut (''Aesculus x carnea'')
Image:Aesculus glabra USDA.jpg|[[Ohio Buckeye]] tree (''Aesculus glabra'')
</gallery>
==References and external links==
{{commons}}
*[http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?245 Germplasm Resources Information Network: ''Aesculus'']
*Forest, F., Drouin, J. N., Charest, R., Brouillet, L., & Bruneau A. (2001). A morphological phylogenetic analysis of Aesculus L. and Billia Peyr. (Sapindaceae). ''Canad. J. Botany'' 79 (2): 154-169. [http://www.ingentaconnect.com/content/nrc/cjb/2001/00000079/00000002/art00003 Abstract].
*[http://www.henriettesherbal.com/eclectic/kings/aesculus.html ''Aesculus glabra'' (Ohio Buckeye)] King's American Dispensatory
* [http://www.homeoint.org/books3/kentmm/aesc-hip.htm ''Aesculus hippocastanum'' (aesc-hip.)] "Kent's Lectures on Homeopathic Materia Medica" by Dr Robert Séror
[[Category:Sapindaceae]]
[[Category:Medicinal plants]]
| color = lightgreen
| name = ''Aesculus'' - Buckeyes and Horse-chestnuts
| image = Horse-chestnut 800.jpg
| image_width = 300px
| image_caption = ''Aesculus hippocastanum''
| regnum = [[Plant]]ae
| divisio = [[flowering plant|Magnoliophyta]]
| classis = [[dicotyledon|Magnoliopsida]]
| ordo = [[Sapindales]]
| familia = [[Sapindaceae]]
| genus = '''''Aesculus'''''
| genus_authority = [[Carolus Linnaeus|L.]]
| subdivision_ranks = Species
| subdivision =
''[[Aesculus arguta]]'': Texas Buckeye<br/>
''[[Aesculus californica]]'': California Buckeye<br/>
''[[Aesculus chinensis]]'': Chinese Horse-chestnut<br/>
''[[Aesculus flava]]'' (''A. octandra''): Yellow Buckeye<br/>
''[[Aesculus glabra]]'': Ohio Buckeye<br/>
''[[Aesculus hippocastanum]]'': Common Horse-chestnut<br/>
''[[Aesculus indica]]'': Indian Horse-chestnut<br/>
''[[Aesculus neglecta]]'': Dwarf Buckeye<br/>
''[[Aesculus parviflora]]'': Bottlebrush Buckeye<br/>
''[[Aesculus pavia]]'': Red Buckeye<br/>
''[[Aesculus sylvatica]]'': Painted Buckeye<br/>
''[[Aesculus turbinata]]'': Japanese Horse-chestnut<br/>
''[[Aesculus wilsonii]]'': Wilson's Horse-chestnut
}}
The genus '''''Aesculus''''' comprises 20–25 species of [[deciduous]] [[tree]]s and [[shrub]]s native to the temperate [[northern hemisphere]], with 7–10 species native to [[North America]] and 13–15 species native in [[Eurasia]]; there are also several natural [[hybrid]]s. They have traditionally been treated in their own usually monogeneric family [[Hippocastanaceae]], but genetic evidence has lead to this family, along with the [[Aceraceae]] ([[Maple]]s and ''[[Dipteronia]]''), being included in the soapberry family ([[Sapindaceae]]).
The North American species are known as '''Buckeyes''' and the Eurasian species as '''Horse-chestnuts'''. Some are also called "White Chestnut" or "Red Chestnut" (as in some of the [[Bach flower remedies]]. In Britain, they are sometimes called "Conker trees" because of their link with the game of [[Conkers]] ).
== Etymology ==
The name Horse-chestnut, hyphenated here to avoid confusion with the true [[chestnut]]s (''Castanea'', [[Fagaceae]]), is also often given as "Horse Chestnut" or "Horsechestnut". One species very popular in cultivation, the Common Horse-chestnut ''Aesculus hippocastanum'' is also often known as just "Horse-chestnut". Linnaeus named the genus ''Aesculus'' after the Roman name for an edible acorn. The use of the term "horse" refers to their strength or inedibility, the word "horse" originally meant strong or powerful, and does not here refer to their fitness as fodder for horses, except in folk etymology. The name buckeye derives from the resemblance of the seed to the brown eye of a buck (male [[deer]]), and horse-chestnut from the external resemblance of the seed to a chestnut, but being inedible. The Buckeye blooms in summer and the Horse-chestnut in late spring.
== Description ==
''Aesculus'' are [[woody plant]]s 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 65 cm across in the Japanese Horse-chestnut ''Aesculus turbinata''); and showy insect-pollinated [[flower]]s, with a single four- or five-lobed petal (actually four or five petals fused at the base). Flowering starts after 80–110 [[growing degree day]]s. The fruit is a rich glossy brown to blackish-brown [[Nut (fruit)|nut]] 2–5 cm diameter, 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 husk has scattered soft spines in some species, spineless in others, and splits into three sections to release the nut.
== Cultivation ==
[[Image:Aesculus carnea BotGartenMuenster PurpurKastanie 6685.jpg|thumb|left|240px|Flower of the Red Horse-chestnut (''Aesculus x carnea'')]]
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 throughout the temperate world. 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, most notably the Red Horse-chestnut ''A. x carnea'', a hybrid between ''A. hippocastanum'' and ''A. pavia''.
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. Common Horse-chestnut is also used as a food plant by [[Sycamore (moth)|The Sycamore]], another species of moth.
Another disease in parts of North West Europe and North America is [[Bleeding canker]] [http://www.forestresearch.gov.uk/bleedingcanker].
==Uses==
The nuts contain high concentrations of a [[saponin]]-class toxin called [[Aesculin]], which is toxic to many animals including humans because it causes [[hemolysis]] (destruction of [[red blood cell]]s). The saponin can be eliminated by leaching the pulverized nuts in multiple changes of boiling water, to yield a wholesome [[starch]]y [[porridge]] once important to some [[Indigenous peoples of the Americas|Native American]] tribes. Some animals, notably [[deer]] and [[squirrel]]s, are resistant to the toxins and can eat the nuts directly. An interesting side-note is that Aesculin is a natural [[pH indicator]] which, when extracted turns from colourless to fluorescent blue under [[UV light]] in an acidic [[pH]] range.
Crushed buckeye nuts have also been thrown into [[lake]]s by [[poaching|poachers]], to kill fish for easy capture.
California Buckeyes ''[[Aesculus californica]]'' are known to cause poisoning of [[honeybee]]s 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 trees are not usually abundant enough in any one area.
The wood is very pale whitish-brown, fairly soft and little-used. Uses include cheap furniture, boxes and firewood.
In several European countries a new disease has been found in several species of ''Aesculus''. For more information check http://www.kastanjeziekte.wur.nl (in Dutch).
In [[United Kingdom|Britain]] and [[Ireland]] the game of [[conkers]] remains a common childhood pastime.
In some cultures, the buckeye tree is thought to bring good luck.[http://www.ohiodnr.com/forestry/education/buckeyetrees2.htm][http://www.biosci.ohio-state.edu/~herb/buckeye.htm]
The [[Mexican Buckeye]] is related to ''Aesculus'', but is in a separate genus, ''Ungnadia''.
===Uses in homeopathic medicine===
Aesculus is used in homeopathic medicine for pain in the sacroiliac region and rectal pain <ref>{{cite book
| last = Morrsion, MD
| first = Roger
| title = Desktop guide to keynotes and comfirmatory symptoms
| publisher =Hahnemann Clinic Publishing
| date = 1993
| location =Grass Valley, CA
| ISBN =0-9635368-0-X}}
</ref>.
== References ==
{{reflist}}
<gallery>
Image:AesculusChinensis.jpg|Chinese Horse-chestnut (''Aesculus chinensis'') young leaves in spring ...
Image:AesculusChinensisLeaf.jpg|... and fully grown, in summer
Image:Aesculus californica.jpg|California Buckeye (''[[Aesculus californica]]'') leaves
Image:Paardekastanje wit uitgelopen knop.jpg|''Aesculus hippocastanum'' bud opening in spring
Image:Horse Chestnut Tree.jpg|[[Common Horse-chestnut]] tree in winter
Image:Kiev kashtan.jpg|[[Common Horse-chestnut]] tree
Image:Aesculus carnea BotGartenMuenster PurpurKastanie 6685.jpg|Red Horse-chestnut (''Aesculus x carnea'')
Image:Aesculus glabra USDA.jpg|[[Ohio Buckeye]] tree (''Aesculus glabra'')
</gallery>
==References and external links==
{{commons}}
*[http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?245 Germplasm Resources Information Network: ''Aesculus'']
*Forest, F., Drouin, J. N., Charest, R., Brouillet, L., & Bruneau A. (2001). A morphological phylogenetic analysis of Aesculus L. and Billia Peyr. (Sapindaceae). ''Canad. J. Botany'' 79 (2): 154-169. [http://www.ingentaconnect.com/content/nrc/cjb/2001/00000079/00000002/art00003 Abstract].
*[http://www.henriettesherbal.com/eclectic/kings/aesculus.html ''Aesculus glabra'' (Ohio Buckeye)] King's American Dispensatory
* [http://www.homeoint.org/books3/kentmm/aesc-hip.htm ''Aesculus hippocastanum'' (aesc-hip.)] "Kent's Lectures on Homeopathic Materia Medica" by Dr Robert Séror
[[Category:Sapindaceae]]
[[Category:Medicinal plants]]
