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Ulmus laevigata

Interesting Facts

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Description

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Family Ulmaceae

Trees or shrubs , evergreen or deciduous. Winter buds with scales , rarely naked; axillary buds developed; terminal bud usually dying back early. Stipules usually membranous, caducous . Leaves simple , alternate or rarely opposite, usually distichous, petiolate ; leaf blade pinnately veined, basally 3(or 5) -veined, margin entire or serrate. Inflorescences axillary . Flowers monochlamydeous , bisexual , or rarely unisexual or polygamous. Perianth lobes 4-9, imbricate or rarely valvate , persistent or caducous. Stamens usually equal in number to and opposite perianth lobes, opposite, basally adnate to tepals; filaments distinct ; anthers 2-celled, longitudinally fissured . Pistil 2-carpellate; ovary superior, 1(or 2) -loculed; ovule 1, suspended, anatropous ; integuments 2. Style very short; stigmas 2, linear . Fruit samara, drupes, or winged nutlets , apically usually with persistent stigmas. Endosperm scanty or absent; embryo erect , curved , or involute ; cotyledons flat, curved, or flexed. Seedling epigeous.

About 16 genera and ca. 230 species: widespread in temperate and tropical areas; eight genera (one endemic) and 46 species (23 endemic) in China.

Recent research strongly suggests that the subfamily Celtidoideae (Aphananthe, Celtis, Gironniera, Pteroceltis, and Trema) is not the closest relative of the subfamily Ulmoideae (Hemiptelea, Ulmus, and Zelkova) . It would probably be more accurate to exclude Celtidoideae from Ulmaceae, and move it to Cannabaceae, rather than treating it as a separate family , Celtidaceae. More data are needed before a stable, new classification of the Urticales can be produced . Until these data are available, it is more practical to retain the traditional circumscription of Ulmaceae.

Most species of this family yield fine timber, the cortex is a good substitute for hemp , the fruit are edible, and the seed oil is used medicinally and industrially. Many species of Ulmaceae are cultivated, and it is not always certain whether specimens are from wild or cultivated plants .[1]

Genus Ulmus

Trees , less often shrubs , to 35 m ; crowns variable. Bark gray, brown, or olive to reddish, tan, or orange, deeply furrowed , sometimes with plates (smooth when young in Ulmus glabra ). Branches unarmed , slender to stout, some with corky wings ; twigs glabrous to pubescent . Leaves sometimes tardily deciduous; stipules falling early. Leaf blade ovate to obovate or elliptic , base usually oblique , sometimes cordate or rounded to cuneate, margins serrate to doubly serrate; venation pinnate. Inflorescences fascicles, racemes , or cymes, pedunculate or subsessile , subtended by 2 bracts. Flowers on branches of previous season , appearing in spring before leaves or in fall , bisexual , pedicellate or sessile; calyx 3-9-lobed; stamens 3-9; styles persistent , deeply 2-lobed. Fruits samaras, usually flattened, membranously winged . x = 14.

Species 20-40: temperate regions , Northern Hemisphere, most in Eurasia .

A recent chloroplast DNA study (S. J. Wiegrefe et al. 1994) has led to the proposal of a new subgeneric and sectional classification of elms. The chloroplast DNA data are supported by morphologic, chemical, and nuclear ribosomal DNA evidence and indicate that the "rock" or hard elms ( Ulmus serotina, U. thomasii, U. crassifolia, and U. alata ) are more closely related than indicated by previous subgeneric treatments (C. K . Schneider 1916; I. A. Grudzinskaya 1980).

Most identification manuals include the introduced species , Ulmus glabra, U. procera, and U. parvifolia, and indicate that they are frequently naturalized . That may well be true. Available herbarium specimens are often inadequately labeled or do not reflect current occurrences. Ease of naturalization can be neither corroborated nor disproved. I include the three species in this treatment because they are known to persist and sometimes naturalize locally where the species have been planted. Extensive field work and collection of U. glabra and U. procera are needed to document their naturalized distributions. Ulmus parvifolia has been widely planted in groves and hedgerows in the Midwest and might well be expected to have become naturalized in more rural settings (S. Shetler, pers. comm. , 1995).

Street and field elms throughout much of North America have been killed by Dutch elm disease . The pathogen responsible for the disease is Ceratocystis ulmi, a fungus native to Europe that was first discovered in North America in Colorado in the 1930s. Since the rapid spread of the disease in the 1960s, much research has been devoted to development of disease-resistant elms (R. J. Stipes and R. J. Campana 1981). Various hybridization projects, including cloning of disease-resistant elms by the American Research Institute, have been started across the country. Ulmus parvifolia and U. pumila have varying degrees of disease resistance and are utilized as shade trees or in breeding programs (see U. pumila below). Apparently Dutch elm disease also affects U. parviflora, U. glabra, and U. procera; certainly the latter two species are more common as seedlings than as trees.[2]

Taxonomy

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Similar Species

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Members of the genus Ulmus

ZipcodeZoo has pages for 75 species, subspecies, varieties, forms, and cultivars in this genus:

U. alata (Winged Elm) · U. alata 'Lace Parasol' (Winged Elm) · U. americana (American Elm) · U. americana 'American Liberty' (American Elm) · U. americana 'Ascendens' (American Elm) · U. americana 'Delaware #2' (American Elm) · U. americana 'Jefferson' (American Elm) · U. americana 'New Harmony' (American Elm) · U. americana 'Pioneer' (Pioneer American Elm) · U. americana 'Princeton' (American Elm) · U. americana 'St Croix' (American Elm 'st. Croix') · U. americana 'Valley Forge' (Valley Forge American Elm) · U. carpinifolia 'Homestead' (Homestead Smoothleaf Elm) · U. crassifolia (Cedar Elm) · U. davidiana (Japanese Elm) · U. glabra (Scots Elm) · U. glabra 'Camperdownii' (Camperdown Elm) · U. laevis (European White Elm) · U. parviflora (Elm) · U. parviflora 'Frontier' (Frontier Elm) · U. parvifolia (Chinese Elm) · U. parvifolia 'Allee' (Allee Lacebark Elm) · U. parvifolia 'Athena' (Chinese Elm) · U. parvifolia 'A. Ross Central Park' (Central Park Splendor Elm) · U. parvifolia 'Bosque' (Chinese Elm) · U. parvifolia 'Brea' (Chinese Elm) · U. parvifolia 'Burgundy' (Chinese Elm) · U. parvifolia 'Catlin' (Chinese Elm) · U. parvifolia 'Central Park Splendor' (Chinese Elm) · U. parvifolia 'Chessins' (Chinese Elm) · U. parvifolia 'Cork Bark' (Chinese Elm) · U. parvifolia 'Corticosa' (Chinese Elm) · U. parvifolia 'Drake' (Chinese Elm) · U. parvifolia 'Dynasty' (Chinese Elm) · U. parvifolia 'D.b. Cole' (Chinese Elm) · U. parvifolia 'Ed Wood' (Chinese Elm) · U. parvifolia 'Elsmo' (Chinese Elm) · U. parvifolia 'Emer II' (Allee® Elm) · U. parvifolia 'Emer I' (Athena® Elm) · U. parvifolia 'Frosty' (Chinese Elm) · U. parvifolia 'Geisha' (Chinese Elm) · U. parvifolia 'Glory' (Chinese Elm) · U. parvifolia 'Hallelujah' (Chinese Elm) · U. parvifolia 'Hokkaido' (Chinese Elm) · U. parvifolia 'Jade Empress' (Chinese Elm) · U. parvifolia 'King's Choice' (Chinese Elm) · U. parvifolia 'Matthew' (Chinese Elm) · U. parvifolia 'Milliken' (Chinese Elm) · U. parvifolia 'Ohio' (Chinese Elm) · U. parvifolia 'Pathfinder' (Chinese Elm) · U. parvifolia 'Red Fall' (Chinese Elm) · U. parvifolia 'Seiju' (Chinese Elm) · U. parvifolia 'Sempervirens' (Chinese Elm) · U. parvifolia 'State Fair' (Chinese Elm) · U. parvifolia 'The Thinker' (Chinese Elm) · U. parvifolia 'True Green' (Chinese Elm) · U. parvifolia 'Yatsubusa' (Chinese Elm) · U. parvifolia 'Zettler' (Chinese Elm) · U. procera (English Elm) · U. pumila (Chinese Elm) · U. pumila 'Beijing Gold' (Siberian Elm) · U. rubra (Red Elm) · U. serotina (September Elm) · U. thomasii (Cork Elm) · U. Vada = 'Wanoux' (Elm [vada]) · U. x hollandica (Dutch Elm) · U. x hollandica 'Jacqueline Hillier' (Dutch Elm) · U. 'Accolade' (Hybrid Elm) · U. 'Arno' (Elm 'arno') · U. 'Fiorente' (Elm 'fiorente') · U. 'Frontier' (Frontier Elm) · U. 'Green King' (Hybrid Elm) · U. 'Patriot' (Hybrid Elm) · U. 'Pioneer' (Hybrid Elm) · U. 'Triumph' (Hybrid Elm)

More Info

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Further Reading

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Notes

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Contributors

Identifiers

Footnotes

  1. Liguo Fu, Yiqun Xin & Alan Whittemore "Ulmaceae". in Flora of China Vol. 5 Page 1. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. Susan L. Sherman-Broyles "Ulmus". in Flora of North America Vol. 3. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/25/2012