aesculus

Aesculus species have stout shoots with resinous, often sticky, buds, with opposite, palmately divided leaves, often very large—to {{convert|65|cm|abbr=on}} across in the Japanese horse chestnut, A. turbinata. Species are deciduous or evergreen. Flowers are showy, insect- or bird-pollinated, with four or five petals fused into a lobed corolla tube, arranged in a panicle inflorescence. Flowering starts after 80–110 growing degree days. The fruit matures to a capsule {{convert|2|-|5|cm|abbr=on|0}} diameter, usually globose, containing one to three seeds (often erroneously called a nut) per capsule. Capsules containing more than one seed result in flatness on one side of the seeds. The point of attachment of the seed in the capsule (hilum) shows as a large, circular, whitish scar. The capsule epidermis has "spines" (botanically: prickles) in some species, while other capsules are warty or smooth. At maturity, the capsule splits into three sections to release the seeds.

Aesculus seeds were traditionally eaten, after leaching, by the Jōmon people of Japan over about four millennia, until 300 AD.

All parts of the buckeye or horse chestnut tree are moderately toxic, including the nut-like seeds. The toxin affects the gastrointestinal system, causing gastrointestinal disturbances. The USDA notes that the toxicity is due to saponin aescin and glucoside aesculin, with alkaloids possibly contributing.

Native Americans used to crush the seeds and the resulting mash was thrown into still or sluggish waterbodies to stun or kill fish. They then boiled and drained (leached) the fish at least three times to dilute the toxin's effects. New shoots from the seeds also have been known to kill grazing cattle.

The genus was considered to be in the ditypic family Hippocastanaceae along with Billia, but phylogenetic analyses of morphological and molecular data have more recently caused this family, along with the Aceraceae (maples and Dipteronia), to be included in the soapberry family (Sapindaceae).

The species of Aesculus include:

The most familiar member of the genus worldwide is the common horse chestnut, Aesculus hippocastanum. 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 is the bottlebrush buckeye, Aesculus parviflora, a 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 Aesculus × carnea, a hybrid between A. hippocastanum and A. pavia.

File:Reims Notre Dame column detail - horse chestnut.jpg depicting horse chestnut tree leaves]]

Interpretations of the tree leaves can be seen in architectural details in the Reims Cathedral.

The horse chestnut was not native to Britain and was only introduced from Europe in 1650 (on the estates of both Dawyck House and Stobo Castle).Scottish Garden Buildings by Tim Buxbaum p.11

The leaf of Aesculus was the official symbol of Kyiv on its coat of arms used from 1969 to 1995. It remains an official symbol of Kyiv to this day.

In the 1840 U.S. presidential campaign, candidate William Henry Harrison called himself the "log cabin and hard cider candidate", portraying himself sitting in a log cabin made of buckeye logs and drinking hard cider, causing Ohio to become known as "the Buckeye State".

In Geneva, Switzerland, an official chestnut tree is used to indicate the beginning of the Spring; every year since 1818, the tree is observed by the secretary of the Grand Council of Geneva (the local parliament), and the opening of the first leaf is recorded and announced publicly. Over the years, four different horse chestnut trees have been used for these recordings.

In North America, several native American tribes, particularly in the western and central United States, such as Miwok, Pomo, Yokut, Maidu, historically used Buckeye trees (Aesculus spp.) like California Buckeye to harvest fish by utilizing the saponins, which had been extracted by the plant's seeds. These tribes used crushed Buckeye nuts to release saponins into streams or shallow water, where the compounds would stun or kill the fish, allowing for easier capture.

• Anne Frank tree

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{{Reflist|refs=

[https://www.pravda.com.ua/articles/2020/05/29/7253616/ {{"'}}Thujoy Khreshchatyk'. Why Kyivans miss chestnuts and how they became a symbol of the capital"], Ukrayinska Pravda (29 May 2019) {{in lang|uk}}

[https://books.google.com/books?id=SAxmDAAAQBAJ&pg=PT153 Carnival Campaign: How the Rollicking 1840 Campaign of "Tippecanoe and Tyler Too" Changed Presidential Elections Forever], by Ronald Shafer, 2016

Sunset Western Garden Book, 1995:606–607

Hardin, JW. 1957. A revision of the American Hippocastanaceae I. Brittonia 9:145-171

Hardin, JW. 1957. A revision of the American Hippocastanaceae II. Brittonia 9:173-195

Hardin, JW. 1960. A revision of the American Hippocastanaceae V, Species of the Old World. Brittonia 12:26-38

{{cite book |last=Harlan |first=Jack R. |title=The Living Fields: Our Agricultural Heritage |year=1995 |publisher=Cambridge Univ. Press |location=Cambridge [u.a.] |isbn=978-0-521-40112-8 |edition=1. publ. |page=15}}

{{cite book |last1=Akazawa |first1=T. |last2=Aikens |first2=C.M. |title=Prehistoric Hunter-Gathers in Japan |date=1986 |publisher=University of Tokyo Press}}

{{cite book |last1=Aikens |first1=C.M. |last2=Higachi |first2=T. |title=Prehistory of Japan |date=1982 |publisher=New York Academic Press}}

{{cite book |last=Hall |first=Alan |date=1976 |title=The Wild Food Trail Guide |edition=second |publisher=Holt, Rhinehart and Winston |location=New York |page=214}}

{{cite book |last=Peterson |first=Lee |date=1977 |title=A field guide to edible wild plants of eastern and central North America |publisher=Houghton Mifflin Co. |location=Boston |pages=172}}

{{cite book |last=Nelson |first=Guy |date=2006 |title=Ohio Buckeye (Aesculus glabra Willd.), Plant Guide |publisher=US Department of Agriculture, Natural Resources Conservation Service |location=Washington, D.C.}}

{{cite book |last1=Dale |first1=Thomas R. |first2=Dixie B. |last2=Scogin |date=1988 |title=100 woody plants of Louisiana |publisher=The Herbarium of Northeast Louisiana University |location=Monroe, Louisiana |pages=118}}

[https://www.primitiveways.com/fish_poison.html Fishing with Poisons]

{{cite journal |last1=Judd |first1=W.S. |first2=R.W. |last2=Sanders |first3=M.J. |last3=Donoghue |date=1994 |title=Angiosperm family pairs |journal=Harvard Papers in Botany |volume=1 |pages=1–51}}

Hardin, JW. 1957. A revision of the American Hippocastanaceae I. Brittonia 9:145-171.

[https://csuvth.colostate.edu/poisonous_plants/Plants/Details/51 Guide to Poisonous Plants]

{{cite journal |last=Harrington |first=Mark G. |author2=Edwards, Karen J. |author3=Johnson, Sheila A. |author4=Chase, Mark W. |author5=Gadek, Paul A. |title=Phylogenetic inference in Sapindaceae sensu lato using plastid matK and rbcL DNA sequences |journal=Systematic Botany |date=Apr–Jun 2005 |volume=30 |issue=2 |jstor=25064067 |pages=366–382 |doi=10.1600/0363644054223549 |s2cid=85868684}}

[http://newyork.plantatlas.usf.edu/Plant.aspx?id=1586 New York Flora Atlas: Aesculus hippocastanum]

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{{Commons category}}

• [https://web.archive.org/web/20090115050608/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). [https://www.researchgate.net/publication/237154605_A_morphological_phylogenetic_analysis_of_Aesculus_L_and_Billia_Peyr_Sapindaceae "A morphological phylogenetic analysis of Aesculus L. and Billia Peyr. (Sapindaceae)"]. Can. J. Bot. 79 (2): 154–169. {{doi|10.1139/b00-146}}.
• [http://www.henriettesherbal.com/eclectic/kings/aesculus.html Aesculus glabra (Ohio buckeye)] King's American Dispensatory
• [https://web.archive.org/web/20090303131928/http://www.portraitoftheearth.com/trees/horsechestnut.html Winter ID pictures]

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Category:Sapindaceae genera

Category:Taxa named by Carl Linnaeus