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''Ulmus rubra'', the slippery elm, is a species of elm native to eastern North America, ranging from southeast North Dakota, east to Maine and southern Quebec, south to northernmost Florida, and west to eastern Texas, where it thrives in moist uplands, although it will also grow in dry, intermediate soils.〔(【引用サイトリンク】 Ulmus rubra Muhl )〕 Other common names include red elm, gray elm, soft elm, moose elm, and Indian elm. The tree was first named as part of ''Ulmus americana'' in 1753, but identified as a separate species, ''Ulmus rubra'', in 1793 by Pennsylvania botanist Gotthilf Muhlenberg. The slightly later name ''U. fulva'', published by French botanist André Michaux in 1803,〔Michaux, A. (1803). ''Flora Boreali-Americana'' ("The Flora of North America")〕 is still widely used in dietary-supplement and alternative-medicine information. The species superficially resembles American elm ''U. americana'', but is more closely related to the European wych elm ''U. glabra'', which has a very similar flower structure, though lacks the pubescence over the seed.〔Elwes, H. J. & Henry, A. (1913). ''(The Trees of Great Britain & Ireland )''. Vol. VII. 1862-4 (as ''U. fulva''). Republished 2004 Cambridge University Press, ISBN 9781108069380〕 ''U. rubra'' was introduced to Europe in 1830.〔 ==Description== ''Ulmus rubra'' is a medium-sized deciduous tree with a spreading head of branches,〔Hillier & Sons. (1990). ''Hillier's Manual of Trees & Shrubs, 5th ed.''. David & Charles, Newton Abbot, UK〕 commonly growing to 12–19 m (40–60 feet), very occasionally < 30 m (100 feet) in height. Its heartwood is reddish-brown, giving the tree its alternative common name 'red elm'. The species is chiefly distinguished from American elm by its downy twigs, red hairy buds, and slimy red inner bark. The broad oblong to obovate leaves are 10–20 cm (4–8 in) long, rough above but velvety below, with coarse double-serrate margins, acuminate apices and oblique bases; the petioles are 6–12mm long.〔Bean, W. J. (1970). ''Trees & Shrubs Hardy in the British Isles'', 8th ed., p.656. (2nd impression 1976) John Murray, London. ISBN 9780719517907〕 The leaves are often red tinged on emergence, turning dark green by summer, and then a dull yellow in the fall;〔(Missouri Botanical Garden, ''Ulmus rubra'' )〕 The perfect, apetalous, wind-pollinated flowers are produced before the leaves in early spring, usually in tight, short-stalked, clusters of 10–20. The reddish-brown fruit is an oval winged samara, orbicular to obovate, slightly notched at the top, 12–18 mm (1/2–3/4 in) long, the single, central seed coated with red-brown hairs, naked elsewhere.〔 Ulmus_rubra_leaf.jpg|Asymmetrical leaf of ''Ulmus rubra'' Mature Ulmus rubra bark.jpg|Mature bark of ''Ulmus rubra'' 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「Ulmus rubra」の詳細全文を読む スポンサード リンク
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