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''Sorbus torminalis'' (syn. ''Torminalis clusii'', wild service tree), sometimes known as the chequer tree or checker tree, is a species of ''Sorbus'' native to Europe from England and Wales east to Denmark and Poland, south to northwest Africa, and southeast to southwest Asia from Asia Minor to the Caucasus and Alborz mountains.〔Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins ISBN 0-00-220013-9.〕 It is a medium-sized deciduous tree growing to 15–25 m tall, with a trunk up to 1.3 m diameter. The bark is smooth and greyish, but flaky, peeling away in squarish plates to reveal darker brown layers. The leaves are 6–14 cm long and broad with a 2.5–5 cm petiole, dark green on both sides, with five to nine acute lobes; the basal pair of lobes are spreading, the rest more forward-pointing and decreasing in size to the leaf apex, and with finely toothed margins; the undersides have small hairs when young, but both sides are smooth and shiny when older; the autumn colour is yellow to red-brown. The flowers are 10–15 mm diameter, with five white petals and 20 creamy-white stamens; they are produced in corymbs 5–12 cm diameter in late spring to early summer, and are hermaphrodite and insect pollinated. The fruit is a globose to ovoid pome 10–15 mm diameter, greenish to russet or brown, patterned with small pale lenticel spots when mature in mid to late autumn.〔〔Mitchell, A. F. (1974). ''A Field Guide to the Trees of Britain and Northern Europe''. Collins ISBN 0-00-212035-6〕〔Blamey, M. & Grey-Wilson, C. (1989). ''Flora of Britain and Northern Europe''. ISBN 0-340-40170-2〕 There are two varieties:〔 * ''Sorbus torminalis'' var. ''torminalis''. Europe, northwest Africa. * ''Sorbus torminalis'' var. ''caucasica''. Caucasus and Alborz Mountains. Leaves less deeply lobed than in var. ''torminalis''. ==Ecology== It is relatively rare and in Britain is now usually confined to pockets of ancient woodland, although it can also be found growing in hedgerows. It can often be found associated with oak and ash woods, preferring clay and lime based soils. In Britain, summer temperatures are often too low for the seeds to ripen, so its principal method of propagation is by suckers.〔 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「Sorbus torminalis」の詳細全文を読む スポンサード リンク
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