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The Kentucky coffeetree, ''Gymnocladus dioicus'',〔Synonyms include American coffee berry, Kentucky mahogany, nicker tree, and stump tree. 〕 is a tree in the subfamily Caesalpinioideae of the pea family Fabaceae, native to the Midwest and Upper South of North America. The seed may be roasted and used as a substitute for coffee beans; however, unroasted pods and seeds are toxic. The wood from the tree is used by cabinetmakers and carpenters. From 1976 to 1994 the Kentucky coffeetree was the state tree of Kentucky, after which the tulip poplar was returned to that designation.〔(【引用サイトリンク】title=Kentucky: Adoption of the Kentucky State Tree )〕 ==Description== Varies from 18 to 21 meters (60–70 feet) high with a spread of 12–15 meters (40–50 feet) and a trunk up to one meter (3 feet) in diameter. A 10-year-old sapling will stand about 4 meters (13 feet) tall. It usually separates 3 to 4½ meters (10–15 feet) from the ground into three or four divisions which spread slightly and form a narrow pyramidal head; or when crowded by other trees, sending up one tall central branchless shaft to the height of 15–21 m (50–70 ft). Branches are stout, pithy, and blunt; roots are fibrous.〔Keeler, Harriet L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scribner's Sons, pp. 109–112.〕 The Kentucky coffeetree is a moderately fast-growing tree, and male trees are often grown in parks and along city streets for ornamental purposes. The tree is typically long-lived, healthy trees living from 100 to 150 years. The Kentucky coffeetree sheds its leaves early during the fall and appears bare for up to 6 months. The naked appearance of the tree is reflected through the Kentucky coffeetree's Greek genus name: γυμνοκλαδυς = "''naked branch''."〔Barnes, Wagner et al. (1977). Michigan Trees〕 Like the Sumac, branches are absent of fine spray; smaller branches are thick and lumpish. Because of the absence of smaller branches and its later leafing, the French in Canada named it Chicot, the dead tree. .〔 The expanding leaves are conspicuous because of the varied colors of the leaflets; the youngest are bright pink, while those which are older vary from green to bronze.〔 The bark is ash-gray and scaly, flaking similarly to black cherry, but more so. The flowers are dioecious, and the fruit is a hard-shelled bean in heavy, woody, thick-walled pods filled with sweet, thick, gooey pulp. Pod length ranges from ; unfertilized female trees may bear miniature seedless pods. The beans contain the toxin cytisine. * Bark: Tan or dark gray, deeply fissured, surface scaly, often with prominent narrow ridges. Branchlets at first coated with short reddish down. * Wood: Light brown; heavy, strong, coarse-grained; durable in contact with the ground, takes a fine polish. Sp. gr., 0.6934; weight of cubic foot, . * Winter buds: Minute, depressed in downy cavities of the stem, two in the axil of each leaf, the smaller sterile. Bud scales two, ovate, coated with brown tomentum and growing with the shoot, become orange green, hairy and about one inch long, before they fall. * Leaves: Alternate, bipinnately compound, ten to fourteen pinnate, lowest pinnae reduced to leaflets, the other seven to thirteen foliate. One to three feet long, eighteen to twenty-four inches broad, by the greater development of the upper pairs of pinnae. Leaf stalks and stalks of pinnae, are terete, enlarged at base, smooth when mature, pale green, often purple on the upper side. Leaflets ovate, two to two and one-half inches long, wedge-shaped or irregularly rounded at base, with wavy margin, acute apex. They come out of the bud bright pink, but soon become bronze green, smooth and shining above. When full grown are dark yellow green above, pale green beneath. In autumn turn a bright clear yellow. Stipules leaf-life, lanceolate, serrate, deciduous. * Flowers: June. Dioecious by abortion, terminal, greenish white. Staminate flowers in a short racemen-like corymb three to four inches (75–100 mm) long, pistillate flowers in a raceme ten to twelve inches (250–300 mm) long. * Calyx: Tubular, hairy, ten-ribbed, five-lobed; lobes valvate in bud, acute, nearly equal. * Corolla: Petals five, oblong, hairy, spreading or reflexed, imbricate in bud. * Stamens: Ten, five long and five short, free, included; filaments thread-like; anthers orange colored, introrse; in the pistillate flower small and sterile. * Pistil: Ovary superior, sessile, hairy, contracted into a short style, with two stigmatic lobes; ovules in two rows. * Fruit: Legume, six to ten inches (150–250 mm) long, one and one-half to two inches wide, somewhat curved, with thickened margins, dark reddish brown with slight glaucous bloom, crowned with remnant of the styles. Stalks and inch or two long. Seeds six to nine, surrounded by a thick layer of dark, sweet pulp.〔 The Kentucky coffeetree is believed to be an example of evolutionary anachronism. The tough, leathery seed pods are too difficult for many animals to chew through (in addition to being poisonous) and they are too heavy for either wind or water dispersal. It is thus believed that the tree would have been browsed upon by now-extinct mammoths and mastodons which ate the pods and nicked the seeds with their large teeth, aiding in germination. This behavior is seen among African Elephants eating ''Fabaceae'' relatives in Africa. Because of this, its prehistoric range may have been much larger than it has been in historical times. Today, in the wild, it only grows well in wetlands, and it is thought that only in such wet conditions can the seed pods rot away to allow germination in the absence of large herbivores.〔 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Kentucky coffeetree」の詳細全文を読む スポンサード リンク
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