CompTIA A+ Certification Exam 220-601
The genus Aesculus, the buckeyes and horse-chestnuts, 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, but recent phyloegentic analysis of morphological and molecular data has led to this family, along with the Aceraceae (Maples 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 Testking 220-602 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 nuts, also called conkers.The name horse-chestnut (hyphenated here to avoid confusion with the true chestnuts (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, 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.Aesculus 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 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 Testking 220-601 fruit is a rich glossy brown to blackish-brown capsule 2–5 cm diameter, usually globose with 1-3 seeds (often erroneously called nuts) per capsule, more than 2 results 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 seedsThe 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 Testking VCP-101V have also been developed, most notably the red horse-chestnut A. × 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 the sycamore, another species of moth.