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''Ailanthus altissima'' ,〔 commonly known as tree of heaven, ailanthus, or in Standard Chinese as ''chouchun'' (), is a deciduous tree in the Simaroubaceae family. It is native to both northeast and central China, as well as Taiwan. Unlike other members of the genus ''Ailanthus'', it is found in temperate climates rather than the tropics. The tree grows rapidly and is capable of reaching heights of in 25 years. However, the species is also short lived and rarely lives more than 50 years, though its remarkable suckering ability makes it possible for this tree to clone itself indefinitely and live considerably longer 〔Collin, Pascal and Dumas, Yann (2009). ("Que savons-nous de l'ailante (Ailanthus altissima (Miller) Swingle) ?" ) (What do we know about A. altissima?). ''Revue forestière française'' 61 (2): 117-130. Cite : ''Mais comme le fait remarquer Kowarik (2007), sa reproduction végétative le rend en quelque sorte très longévif, le premier individu introduit aux États-Unis en 1784 étant toujours présent grâce à ses drageons.'' (But as it is mentioned by Kowarik (2007), vegetative reproduction makes (altissima ) very long-lived, in a way. The first individual planted in the United States in 1784 is still there thanks to its suckers.)〕 (since they are linked to the mother tree and thus partly fed by it, the suckers are less vulnerable than the seedlings and can grow faster). In China, the tree of heaven has a long and rich history. It was mentioned in the oldest extant Chinese dictionary and listed in countless Chinese medical texts for its purported ability to cure ailments ranging from mental illness to baldness. The roots, leaves and bark are still used today in traditional Chinese medicine, primarily as an astringent. The tree has been grown extensively both in China and abroad as a host plant for the ailanthus silkmoth, a moth involved in silk production. Ailanthus has become a part of western culture as well, with the tree serving as the central metaphor and subject matter of the best-selling American novel ''A Tree Grows in Brooklyn'' by Betty Smith. The tree was first brought from China to Europe in the 1740s and to the United States in 1784. It was one of the first trees brought west during a time when ''chinoiserie'' was dominating European arts, and was initially hailed as a beautiful garden specimen. However, enthusiasm soon waned after gardeners became familiar with its suckering habits and its foul smelling odour. Despite this, it was used extensively as a street tree during much of the 19th century. Outside of Europe and the United States, the plant has been spread to many other areas beyond its native range. In a number of these, it has become an invasive species due to its ability both to colonise disturbed areas quickly and to suppress competition with allelopathic chemicals. It is considered a noxious weed in Australia, the United States, New Zealand and many countries of central, eastern and southern Europe. The tree also resprouts vigorously when cut, making its eradication difficult and time consuming. In many urban areas, it has acquired the derisive nicknames of "ghetto palm", "stink tree", and "tree of Hell". ==Description== ''A. altissima'' is a medium-sized tree that reaches heights between 17 and 27 metres (56 and 90 ft) with a diameter at breast height of about 1 metre (40 in).〔 The bark is smooth and light grey, often becoming somewhat rougher with light tan fissures as the tree ages. The twigs are stout, smooth to lightly pubescent, and reddish or chestnut in colour. They have lenticels as well as heart-shaped leaf scars (i.e. a scar left on the twig after a leaf falls) with many bundle scars (i.e. small marks where the veins of the leaf once connected to the tree) around the edges. The buds are finely pubescent, dome shaped, and partially hidden behind the petiole, though they are completely visible in the dormant season at the sinuses of the leaf scars.〔 The branches are light to dark gray in colour, smooth, lustrous, and containing raised lenticels that become fissures with age. The ends of the branches become pendulous. All parts of the plant have a distinguishing strong odour that is often likened to peanuts, cashews,〔 or rotting cashews. The leaves are large, odd- or even-pinnately compound, and arranged alternately on the stem. They range in size from in length and contain 10–41 leaflets organised in pairs, with the largest leaves found on vigorous young sprouts. When they emerge in the spring, the leaves are bronze then quickly turn from medium to dark green as they grow.〔 The rachis is light to reddish-green with a swollen base. The leaflets are ovate-lanceolate with entire margins, somewhat asymmetric and occasionally not directly opposite to each others. Each leaflet is long and wide. They have a long tapering end while the bases have two to four teeth, each containing one or more glands at the tip.〔 The leaflets' upper sides are dark green in colour with light green veins, while the undersides are a more whitish green. The petioles are long.〔 The lobed bases and glands distinguish it from similar sumac species. The flowers are small and appear in large panicles up to in length at the end of new shoots. The individual flowers are yellowish green to reddish in colour, each with five petals and sepals.〔〔 The sepals are cup-shaped, lobed and united while the petals are valvate (i.e. they meet at the edges without overlapping), white and hairy towards the inside.〔〔〔 They appear from mid-April in the south of its range to July in the north. ''A. altissima'' is dioecious, with male and female flowers being borne on different individuals. Male trees produce three to four times as many flowers as the females, making the male flowers more conspicuous. Furthermore, the male plants emit a foul-smelling odour while flowering to attract pollinating insects. Female flowers contain ten (or rarely five through abortion) sterile stamens (stamenoides) with heart-shaped anthers. The pistil is made up of five free carpels (i.e. they are not fused), each containing a single ovule. Their styles are united and slender with star-shaped stigmas.〔〔 The male flowers are similar in appearance, but they of course lack a pistil and the stamens do function, each being topped with a globular anther and a glandular green disc.〔 The fruits grow in clusters; a fruit cluster may contain hundreds of seeds.〔 The seeds borne on the female trees are 5 mm in diameter and each is encapsulated in a samara that is 2.5 cm long (1 in) and broad, appearing July though August, but can persist on the tree until the next spring. The samara is large and twisted at the tips, making it spin as it falls, assisting wind dispersal,〔〔 and aiding buoyancy for long-distance dispersal through hydrochory.〔 The females can produce huge amounts of seeds, normally around 30,000 per kilogram (14,000/lb) of tree,〔 and fecundity can be estimated non-destructively through measurements of dbh.〔 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「Ailanthus altissima」の詳細全文を読む スポンサード リンク
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