| 词条 | Ulmus crassifolia | |
| 释义 |
| image = Ulmus crassifolia leaves.jpeg | status = LC | status_system = IUCN3.1 | status_ref=[1] | display_parents = 2 | genus = Ulmus | parent = Ulmus sect. Trichoptelea | species = crassifolia | authority = Nutt. | range_map = Ulmus crassifolia range map 4.png | range_map_caption = Natural range (Florida population excluded) | synonyms =
}}Ulmus crassifolia Nutt., the Texas cedar elm or simply cedar elm, is a deciduous tree native to south central North America, mainly in southern and eastern Texas, southern Oklahoma, Arkansas and Louisiana, with small populations in western Mississippi, southwest Tennessee and north central Florida;[2] it also occurs in northeastern Mexico.[3][4] It is the most common elm tree in Texas. The tree typically grows well in flat valley bottom areas referred to as 'Cedar Elm Flats'. The common name 'cedar elm' is derived from the trees' association with juniper trees, locally known as cedars.[5] DescriptionThe cedar elm is a medium to large deciduous tree growing to 24–27 m tall with a rounded crown. The leaves are small, 2.5–5 cm long by 1.3–2 cm broad, with an oblique base, and distinguish it from Ulmus serotina with which it readily hybridizes in the wild. Leaf fall is late, often in early winter. The wind-pollinated apetalous perfect flowers are produced in the late summer or early fall; they are small and inconspicuous, with a reddish-purple color. The fruit is a small winged samara 8–10 mm long, maturing quickly after the flowering in late fall.[6][7] Pests and diseasesCedar elm is susceptible to Dutch elm disease (DED), though less so than American elm, and moderately damaged by the elm leaf beetle Xanthogaleruca luteola. The tree also suffers from a vascular wilt, the symptoms often confused with those of DED. Cedar elms are very susceptible to mistletoe. Mistletoe is a parasite that roots itself in to the vascular system of the tree, thus stealing valuable nutrients and water. In some cases, if not removed the parasite can be devastating to large sections of trees and even fatal. They create club like branches that die out at the ends. These "club" branches create openings for future pests like the elm beetles and carpenter ants. There are no known treatments that are safe enough to kill mistletoe without killing the tree. Removing the mistletoe manually is not a guarantee, however it is the best known method for control.{{citation needed|date=January 2014}} CultivationIt is extremely rare in cultivation in Europe,[8] and Australasia.[9] Henry (1913) and Bean (1988) note that it does not thrive in northern Europe, where the branchlets often die back.[8][10] Specimens supplied by the Späth nursery to the Royal Botanic Garden Edinburgh in 1902 as U. crassifolia may survive in Edinburgh as it was the practice of the garden to distribute trees about the city (viz. the Wentworth elm).[11] Notable treesThe USA National Champion, measuring 37 m high in 2001, grows in the Meeman-Shelby Forest State Park Tennessee.[12] Cultivars
Hybrids
AccessionsNorth America
Europe
Australasia
NurseriesNorth AmericaWidely available Europe
AustralasiaNone known. References1. ^{{Cite web|url=https://www.iucnredlist.org/species/61966946/61966949|title=The IUCN Red List of Threatened Species|website=IUCN Red List of Threatened Species|access-date=2018-10-27}} {{Elm species, varieties, hybrids, hybrid cultivars and species cultivars |state=collapsed}}2. ^{{cite web|url=http://www.efloras.org/object_page.aspx?object_id=7179&flora_id=1 |title=Map: Ulmus crassifolia |publisher=Efloras.org |date= |accessdate=2013-09-01}} 3. ^Todzia, C. A. & Panero, J. L. (2006). A new species of Ulmus (Ulmaceae) from southern Mexico and a synopsis of the species in Mexico. Brittonia, Vol 50, (3): 346 4. ^{{cite web|jstor=2807778|title=A New Species of Ulmus (Ulmaceae) from Southern Mexico and a Synopsis of the Species in Mexico}} 5. ^http://npsot.org/wp/story/2011/1687/ 6. ^{{cite web|url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233501326 |title=Ulmus crassifolia in Flora of North America @ |publisher=Efloras.org |date= |accessdate=2013-09-01}} 7. ^{{cite web|url=http://plants.usda.gov/java/profile?symbol=ulcr |title=Plants Profile for Ulmus crassifolia (cedar elm) |publisher=Plants.usda.gov |date= |accessdate=2013-09-01}} 8. ^1 Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Republished 2004 Cambridge University Press, {{ISBN|9781108069380}} 9. ^{{cite journal|first1=Mike|last1=Wilcox|first2=Chris|last2=Inglis|journal=Auckland Botanical Society Journal|title=Auckland's elms|volume=58|issue=1|date=2003|pages=38–45|publisher=Auckland Botanical Society|url=http://bts.nzpcn.org.nz/bts_pdf/ABJ58%281%292003-38-45-Elms.pdf}} 10. ^Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London 11. ^{{cite book |date=1902|title=Accessions book|publisher=Royal Botanic Garden Edinburgh|pages=45, 47|url=https://commons.wikimedia.org/wiki/File:Royal_Botanic_Garden_Edinburgh._(1902)._Accessions_book_pages_45,47.jpg}} 12. ^American Forests. (2012). The 2012 National Register of Big Trees. 13. ^{{cite web|url=http://www.cirrusimage.com/tree_cedar_elm.htm |title=''Ulmus crassifolia'' at Morton Arboretum |publisher=Cirrusimage.com |date=2010-05-06 |accessdate=2013-09-14}} 14. ^{{cite web|author=Ramon Jordan |url=http://www.usna.usda.gov/ |title=US National Arboretum: |publisher=Usna.usda.gov |date= |accessdate=2013-09-01}} 15. ^{{cite web|url=http://www.arboretum-waasland.be/English.htm |title=English |publisher=Arboretum-waasland.be |date= |accessdate=2013-09-01}} External links
9 : Ulmus|Trees of the United States|Trees of the Southeastern United States|Trees of the South-Central United States|Trees of the Southern United States|Plants used in bonsai|Ulmus articles with images|Elm species and varieties|Ulmus Edinburgh Spath 1902 |
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