94,129
edits
Changes
no edit summary
{{SPlantbox
|familia=Ulmaceae
|genus=Ulmus
|species=thomasii
|common_name=Cork Elm, Rock Elm
|name_ref=Flora - A Gardener's Encyclopedia
|habit=tree
|habit_ref=Flora - A Gardener's Encyclopedia
|Max ht box=100
|Max ht metric=ft
|height_ref=Flora - A Gardener's Encyclopedia
|Max wd box=40
|Max wd metric=ft
|width_ref=Flora - A Gardener's Encyclopedia
|lifespan=perennial
|exposure=sun
|sun_ref=Flora - A Gardener's Encyclopedia
|Temp Metric=°F
|min_zone=2
|usda_ref=Flora - A Gardener's Encyclopedia
|max_zone=9
|image=Upload.png
|image_width=240
}}
'''''Ulmus thomasii''''' <small>Sarg.</small>, the '''Rock Elm''' or '''Cork Elm''', is a [[deciduous]] tree native primarily to the [[Midwestern]] [[United States]]. The tree ranges from southern [[Ontario]] and [[Quebec]], south to [[Tennessee]], west to northeastern [[Kansas]], and north to [[Minnesota]].<ref>http://esp.cr.usgs.gov/data/atlas/little/ulmuthom.pdf</ref> Its preferred habitat is moist but well-drained sandy loam, loam, or silt loam soil, mixed with other [[hardwood]]s; it is moderately shade-tolerant [http://forestry.about.com/library/silvics/blsilulmtho.htm]. However, it also grows on dry uplands, especially on rocky ridges and [[limestone]] bluffs.
The tree grows from 15-30 m tall and may live up to 300 years. Where forest-grown, the crown is cylindrical and upright with short branches, and is narrower than most other elms. Rock Elm is also unusual among elms in that it usually has a [[monopodial]] growth habit. <ref name=Bean> Bean, W. J. (1981). ''Trees and shrubs hardy in Great Britain'', 7th edition. Murray, London. </ref>. The [[bark]] is grey-brown and deeply furrowed into scaly, flattened ridges. Many older branches have 3-4 irregular thick corky wings. It is for this reason the Rock Elm is sometimes called the Cork Elm.
The [[leaf|leaves]] are 5 - 10 cm long and 2 - 5 cm wide, [[leaf shape|oval]] to [[leaf shape|obovate]] with a round, symmetrical base and acuminate apex. The leaf surface is shiny dark green, turning bright yellow in autumn; the underside is pubescent. The [[perfect flower|perfect]] [[apetalous]], wind pollinated [[flower]]s are red-green and appear in racemes < 40 mm long two weeks before the leaves from March to May, depending on the tree's location. The [[fruit]] is a broad ovate [[Samara (fruit)|samara]] 13 - 25 mm long covered with fine hair, notched at the tip, and maturing during May or June to form drooping clusters at the leaf bases. <ref name=White>White, J & More, D. (2003). ''Trees of Britain & Northern Europe''. Cassell's, London.</ref>.
{{Inc|
{{Inc|
Ulmus racemosa, Thomas, not Borkh. (U. Thomasii, Sarg.). Cork Elm. Rock Elm. Fig. 3877. Tree, attaining 100 ft., with short spreading branches, forming an oblong round-topped head: branchlets pubescent usually until the second year and mostly irregularly corky winged when older: buds acute, pubescent: lvs. oval to oblong-obovate, unequal at the base, shortly acuminate, sharply and doubly serrate, glabrous or somewhat rough above, pubescent beneath, 2-4 in. long: fls. in slender pendulous racemes; calyx with 5-8 exserted stamens: fr. oval or obovate, with a shallow notch at the apex, pale, pubescent, 1/2 – 3/4 in. long. Que. to Tenn., west to Neb. S.S. 7:312.
Ulmus racemosa, Thomas, not Borkh. (U. Thomasii, Sarg.). Cork Elm. Rock Elm. Tree, attaining 100 ft., with short spreading branches, forming an oblong round-topped head: branchlets pubescent usually until the second year and mostly irregularly corky winged when older: buds acute, pubescent: lvs. oval to oblong-obovate, unequal at the base, shortly acuminate, sharply and doubly serrate, glabrous or somewhat rough above, pubescent beneath, 2-4 in. long: fls. in slender pendulous racemes; calyx with 5-8 exserted stamens: fr. oval or obovate, with a shallow notch at the apex, pale, pubescent, 1/2 – 3/4 in. long. Que. to Tenn., west to Neb.
}}
}}
==Cultivation==
===Propagation===
===Pests and diseases===
Like most North American elms, the Rock Elm is very susceptible to [[Dutch elm disease]].
==Varieties==
==Gallery==
<gallery perrow=5>
Image:Upload.png| photo 1
Image:Upload.png| photo 2
Image:Upload.png| photo 3
</gallery>
==References==
<references/>
<!--- xxxxx *Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381 -->
<!--- xxxxx *American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432 -->
<!--- xxxxx *Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608 -->
==External links==
*{{wplink}}
{{stub}}
__NOTOC__