Aesculus

For the Ancient Greek playwright, see Aeschylus.

Aesculus
Aesculus hippocastanum
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Sapindales
Family:	Sapindaceae
Subfamily:	Hippocastanoideae
Genus:	Aesculus L.
Species
Aesculus arguta Aesculus californica Aesculus × carnea Aesculus chinensis Aesculus chinensis var. wilsonii Aesculus flava (A. octandra) Aesculus glabra Aesculus hippocastanum Aesculus indica Aesculus neglecta Aesculus parviflora Aesculus parryi Aesculus pavia Aesculus sylvatica Aesculus turbinata Aesculus wangii = Aesculus assamica

Aesculus glabra Ohio buckeye

Flower of Aesculus x carnea, the red Horse Chestnut

The genus Aesculus ( /ˈɛskjʊləs/^[1] or /ˈaɪskjʊləs/) comprises 13-19 species of woody trees and shrubs native to the temperate northern hemisphere, with 6 species native to North America and 7-13 species native to Eurasia; there are also several hybrids. Species are deciduous or evergreen. This genus has traditionally been treated in the ditypic family Hippocastanaceae along with Billia,^[2] but recent phylogenetic analysis of morphological^[3] and molecular data^[4] has led to this family, along with the Aceraceae (Maples and Dipteronia), being included in the soapberry family (Sapindaceae).

Linnaeus named the genus Aesculus after the Roman name for an edible acorn. The Eurasian species are known as horse chestnuts while the North American species are called buckeyes. 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, played with the seeds, also called conkers. Aesculus seeds were traditionally eaten, after leaching, by the Jomon people of Japan over about 4 millennia, until 300AD.^[5]

Description

Aesculus species are woody plants from 4 to 36m 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). Flowers are showy, insect-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, 2–5 cm diameter, usually globose, containing 1-3 seeds (often erroneously called a nut) per capsule. Capsules containing more than one seed result in seeds being flat on one side. 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, other capsules are warty or smooth; capsule splits into three sections to release the seeds.^[6][7][8]

The species of Aesculus include:

• Aesculus arguta: Texas buckeye
• Aesculus californica: California buckeye
• Aesculus × carnea: red horse chestnut
• Aesculus chinensis: Chinese horse chestnut
• Aesculus chinensis var. wilsonii: Wilson's horse chestnut
• Aesculus flava (A. octandra): yellow buckeye
• Aesculus glabra: Ohio buckeye
• Aesculus hippocastanum: common horse chestnut
• Aesculus indica: Indian horse chestnut
• Aesculus neglecta: dwarf buckeye
• Aesculus parviflora: bottlebrush buckeye
• Aesculus parryi
• Aesculus pavia: red buckeye
• Aesculus pavia var. flavescens: Texas yellow buckeye, yellow woolly buckeye
• Aesculus sylvatica: painted buckeye
• Aesculus turbinata: Japanese horse chestnut
• Aesculus wangii = Aesculus assamica

Cultivation

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 Aesculus × carnea, a hybrid between A. hippocastanum and A. pavia.

References

1. ^ Sunset Western Garden Book, 1995:606–607
2. ^ Hardin, JW. 1957. A revision of the American Hippocastanaceae I. Brittonia 9:145-171.
3. ^ Judd, WS, RW Sanders, MJ Donoghue. 1994. Angiosperm family pairs. Harvard Papers in Botany. 1:1-51.
4. ^ MG Harrington, KJ Edwards, SA Johnson, MW Chase. 2005. Phylogenetic inference in Sapindaceae sensu lato using plastid matK and rbcL DNA sequences. Systematic Botany. 30:366–382
5. ^ ISBN 0 521 40112 7 _The Living Fields_, by Harlan Jack Rodney, University Press, Cambridge, Great Britain,1995 :15 Harlan cites AkazawaT & AikensCM 1986 _Prehistoric Hunter-Gathers in Japan_ Univ. Tokyo Press, and cites AikensCM & HigachiT1982 _Prehistory of Japan_ NY Academic Press.
6. ^ Hardin, JW. 1957. A revision of the American Hippocastanaceae I. Brittonia 9:145-171
7. ^ Hardin, JW. 1957. A revision of the American Hippocastanaceae II. Brittonia 9:173-195
8. ^ Hardin, JW. 1960. A revision of the American Hippocastanaceae V, Species of the Old World. Brittonia 12:26-38

External links

Media related to Aesculus at Wikimedia Commons Data related to Aesculus at Wikispecies

• 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. Abstract.
• Aesculus glabra (Ohio buckeye) King's American Dispensatory
• Winter ID pictures