Ulmus thomasii

Species of tree

"Rock Elm" redirects here. For other uses, see Rock Elm (disambiguation).

Rock elm

Rock elm, Meise.

Conservation status

Least Concern  (IUCN 3.1)[1]

Scientific classification
Kingdom:  | Plantae
Clade:  | Tracheophytes
Clade:  | Angiosperms
Clade:  | Eudicots
Clade:  | Rosids
Order:  | Rosales
Family:  | Ulmaceae
Genus:  | Ulmus
Subgenus:  | U. subg. Oreoptelea
Section:  | U. sect. Chaetoptelea
Species:  |

U. thomasii

Binomial name
Ulmus thomasii

Sarg.

Natural range of Ulmus thomasii
Synonyms[2]

* Ulmus racemosa Thomas

Ulmus thomasii, the rock elm[3] or cork elm (or orme liège in Québec), 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.[4]

## Etymology

[edit]

The tree was named in 1902 for David Thomas, an American civil engineer who had first named and described the tree in 1831 as Ulmus racemosa.[5]

## Description

[edit]

Ulmus thomasii grows as a tree from 15–30 m (50–100 ft) tall, and may live for up to 300 years. Where forest-grown, the crown is cylindrical and upright with short branches, and is narrower than most other elms.[6] Rock elm is also unusual among North American elms in that it is often monopodial.[7] 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.[8]

The leaves are 5–10 cm (2–4 in) long and 2–5 cm (3⁄4–2 in) wide, oval to obovate with a round, symmetrical base and acuminate apex.[9] The leaf surface is shiny dark green, turning bright yellow in autumn; the underside is pubescent. The perfect apetalous, wind-pollinated flowers are red-green and appear in racemes up to 40 mm (2 in) long two weeks before the leaves from March to May, depending on the tree's location. The fruit is a broad ovate samara 13–25 mm (1⁄2–31⁄32 in) long covered with fine hair, notched at the tip, and maturing during May or June to form drooping clusters at the leaf bases.[10]

Although U. thomasii is protandrous, levels of self-pollination remain high.[11]

* U. racemosa [:U. thomasii] diagnostic illustration (1865)

* U. racemosa [:U. thomasii] diagnostic illustration (1900)

* U. thomasii shoot and buds (1920)

* U. thomasii new leaves, Meisse

* U. thomasii August leaves on short shoot, Jamesville, New York

* U. thomasii leaves, Sir Harold Hillier Gardens, England

* U. thomasii bark, Meisse

* U. thomasii young bark

* U. thomasii corky twig, Meisse

## Ecology

[edit]

Ulmus thomasii is moderately shade-tolerant.[12] Its preferred habitat is moist but well-drained sandy loam, loam, or silt loam soil, mixed with other hardwoods. However, it also grows on dry uplands, especially on rocky ridges and limestone bluffs.

## Pests and diseases

[edit]

Like most North American elms, U. thomasii is very susceptible to Dutch elm disease.

## Cultivation

[edit]

There are no known cultivars of Ulmus thomasii, nor is it known to be any longer in commerce. It appeared in some US nursery catalogues in the early 20th century.[13][14][15] It has, however, been planted as a street tree in Cheyenne, Wyoming, where in tight lines it keeps a monopodial habit recalling Jersey elm.[16] The species is occasionally grown beyond its native range as a specimen tree in botanical gardens and arboreta, for example in northwestern Europe, but not commonly cultivated in northern Europe, being unsuited to the region's more temperate, maritime climate. However, the tree was propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire, from 1965 to 1977, during which time 49 were sold.[17][18]

Ulmus thomasii was crossed experimentally with Japanese elm (U. davidiana var. japonica) at the Arnold Arboretum in Massachusetts, but no clones were released to commerce.[11] Seedlings arising from crossings with Siberian elm (U. pumila) at the Lake States Forestry Experimental Station in the 1950s all perished,[19] a classic case of hybrid lethality.[20]

## Notable trees

[edit]

The US National Champion, measuring 100 ft (30 m) high in 1989, grows in Cass County, Michigan.[21]

## Uses

[edit]

The wood of the rock elm is the hardest and heaviest of all elms, and where forest-grown remains comparatively free of knots and other defects. It is also very strong and takes a high polish, and consequently was once in great demand in America and Europe for a wide range of uses, notably boatbuilding, furniture, agricultural tools, and musical instruments.

Much of the timber's strength is derived from the tight grain arising from the tree's very slow rate of growth, the trunk typically increasing in diameter by less than 2 mm (3⁄32 in) a year. Over 250 annual growth rings were once counted in a log 24 cm (9+1⁄2 in) square being sawn for gunwales in an English boatyard, while a tree once grown at Kew Gardens, London, attained a height of only 12 m (39 ft) in 50 years.[22]

## Accessions

[edit]

North America

* Arnold Arboretum, Massachusetts, US. Acc. no. 444-88.
* Brenton Arboretum, Dallas Center, Iowa, US. No acc. details available.
* Dominion Arboretum, Ottawa, Canada. No acc. details.
* Morton Arboretum, Illinois, US. Acc. no. 178-84, wild collected from Reedsville, Wisconsin; 843-2005 (Kelleys Island, Erie County, Ohio); 122-2006 (Dixon County, Nebraska).
* Nebraska Statewide Arboretum, US. No details available.

Europe

* Grange Farm Arboretum, Lincolnshire, UK. Acc. no. 706.
* National Botanic Garden of Belgium, Meise, Belgium. Acc. no. 19800105.
* National Botanic Gardens, Ireland,[23] Glasnevin, Ireland. Location: A3 (155)
* Sir Harold Hillier Gardens, Hampshire, UK. Acc. no. 2008.0419, wild collected in Ontario, Canada, by Kristl Walek
* Wakehurst Place Garden Wakehurst Place, UK. Acc. no. 1968-48603.

## References

[edit]

Wikimedia Commons has media related to Ulmus thomasii.

1. ^ Stritch, L. (2018). "Ulmus thomasii". IUCN Red List of Threatened Species. 2018: e.T61967392A61967401. doi:10.2305/IUCN.UK.2018-1.RLTS.T61967392A61967401.en. Retrieved 18 November 2021.
2. ^ "Ulmus thomasii". Tropicos. Missouri Botanical Garden.
3. ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
4. ^ "Ulmus Thomasii Range Map" (PDF). United States Geological Survey. Retrieved 2008-03-02.
5. ^ This name had been used in 1800 for a different species of elm, hence the need for the later renaming that honored Thomas.
6. ^ Photographs of mature Rock Elm showing narrow profile: Virginia Tech Department of Forest Resources [1], Natural Resources of Canada, tidcf.nrcan.gc.ca [2] Archived 2016-08-02 at the Wayback Machine [3]
7. ^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London.
8. ^ Photograph of corky ridges of Rock Elm branches, Michigan State University Plant Encyclopedia [4]
9. ^ "Herbarium specimen - WAG.1846088". Botany catalogues. Naturalis Biodiversity Center. U. thomasii leaves specimen, Quebec, 1932; "Herbarium specimen - L.1582468". Botany catalogues. Naturalis Biodiversity Center. U. thomasii leaves specimen, Arnold Arboretum, 1960
10. ^ White, J & More, D. (2003). Trees of Britain & Northern Europe. Cassell's, London.
11. ^ a b Hans, A. S. (1981). "Compatibility and Crossability Studies in Ulmus". Silvae Genetica. 30: 4–5.
12. ^ "Forestry".
13. ^ Kelsey, Frederick W., Choice Trees, cat. 55, N.Y. 1906, p.20
14. ^ Griffing's tree & plant book, 1929; Griffing's Interstate Nurseries, C.M. Griffing & Company;p.29
15. ^ Griffing's tree & plant book, 1930; Griffing's Interstate Nurseries; p 20
16. ^ Justin Evertson, 'The Value of Large Trees', The Seed, Spring 2007, p.6, Nebraska Statewide Arboretum
17. ^ Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.
18. ^ Hillier & Sons Sales inventory 1962 to 1977 (unpublished).
19. ^ Sholtz, H. F. (1957). Rock Elm (Ulmus thomasii). Lake States Forest Experimental Station Paper 47:16.
20. ^ Mino, Masanobu; Maekawa, Kenji; Ogawa, Ken'Ichi; Yamagishi, Hiroshi; Inoue, Masayoshi (2002). "Cell Death Processes during Expression of Hybrid Lethality in Interspecific F1 Hybrid between Nicotiana gossei Domin and Nicotiana tabacum". Plant Physiology. 130 (4): 1776–1787\. doi:10.1104/pp.006023. PMC 166689. PMID 12481061.
21. ^ "Rock Elm (Ulmus thomasii)". The 2012 National Register of Big Trees. American Forests. 2012.
22. ^ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. 1848–1929. Republished 2004 Cambridge University Press, ISBN 978-1-108-06938-0
23. ^ "The National Botanic Gardens of Ireland".

## External links

[edit]

* U. thomasii, Flora of North America, www.efloras.org
* Brian Pruka, Ulmus thomasii: 'The Hard Elm That's Hard to Find', Arnoldia, Volume 74, Issue 1, 2016

* v
* t
* e

Elm species, varieties, hybrids, hybrid cultivars and species cultivars

Species, varieties and subspecies|

* U. alata (Winged elm)
* U. americana (American elm)
* U. americana var. floridana (Florida elm)
* U. bergmanniana (Bergmann's elm)
* U. bergmanniana var. bergmanniana
* U. bergmanniana var. lasiophylla
* U. castaneifolia (Chestnut-leafed or multinerved elm)
* U. changii (Hangzhou elm)
* U. changii var. changii
* U. changii var. kunmingensis (Kunming elm)
* U. chenmoui (Chenmou or Langya Mountain elm)
* U. chumlia
* U. crassifolia (Cedar or Texas cedar elm)
* U. davidiana (David or Father David elm)
* U. davidiana var. davidiana
* U. davidiana var. japonica (Japanese elm)
* U. elongata (Long raceme elm)
* U. gaussenii (Anhui or hairy elm)
* U. glabra (Wych or scots elm)
* U. glaucescens (Gansu elm)
* U. glaucescens var. glaucescens
* U. glaucescens var. lasiocarpa (hairy-fruited glaucescent elm)
* U. harbinensis (Harbin elm)
* U. ismaelis
* U. laciniata (Manchurian cut-leaf or lobed elm)
* U. laciniata var. nikkoensis (Nikko elm)
* U. laevis (European white elm)
* U. laevis var. celtidea
* U. laevis var. parvifolia
* U. laevis var. simplicidens
* U. lamellosa (Hebei elm)
* U. lanceifolia (Vietnam elm)
* U. macrocarpa (Large-fruited elm)
* U. macrocarpa var. glabra
* U. macrocarpa var. macrocarpa
* U. mexicana (Mexican elm)
* U. microcarpa (Tibetan elm)
* U. minor (Field elm)
* U. minor subsp. minor
* U. minor var. italica
* U. parvifolia (Chinese or lacebark elm)
* U. parvifolia var. coreana (Korean elm)
* U. prunifolia (Cherry-leafed elm)
* U. pseudopropinqua (Harbin spring elm)
* U. pumila (Siberian elm)
* U. rubra (Slippery elm)
* U. serotina (September elm)
* U. szechuanica (Szechuan (Sichuan) or red-fruited elm)
* U. thomasii (Rock or cork elm)
* U. uyematsui (Alishan elm)
* U. villosa (Cherry-bark or marn elm)
* U. wallichiana (Himalayan or kashmir elm)
* U. wallichiana subsp. wallichiana
* U. wallichiana subsp. xanthoderma
* U. wallichiana var. tomentosa

Disputed species, varieties and subspecies|

* U. boissieri
* U. minor subsp. canescens (Grey, grey-leafed or hoary elm)
* U. elliptica

Hybrids|

* U. davidiana var. japonica × U. minor
* U. × arbuscula
* U. × arkansana
* U. × brandisiana
* U. × diversifolia
* U. × hollandica (Dutch elm)
* U. × hollandica var. insularum
* U. × intermedia
* U. × mesocarpa

Species cultivars|

| American elm|

* American Liberty
* Ascendens
* Augustine
* Aurea
* Beaverlodge
* Beebe's Weeping
* Brandon
* Burgoyne
* JFS Prince II
* College
* Columnaris
* Creole Queen
* Deadfree
* Delaware
* Exhibition
* Fiorei
* Flick's Spreader
* Folia Aurea Variegata
* Great Plains
* Hines
* Incisa
* Independence
* Iowa State
* Jackson
* Jefferson
* Kimley
* Klehmii
* L'Assomption
* Lake City
* Lewis & Clark
* Littleford
* Maine
* Markham
* Miller Park
* Minneapolis Park
* Moline
* Morden
* New Harmony
* Nigricans
* Patmore
* Pendula
* Penn Treaty
* Princeton
* Pyramidata
* Queen City
* Sheyenne
* Skinner Upright
* St. Croix
* Star
* Valley Forge
* Variegata
* Vase
* Washington

|

Cedar elm|

* Brazos Rim

Chinese elm|

* A-1
* A. Ross Central Park
* Blizzard
* BSNUPF
* Burgundy
* Burnley Select
* Catlin
* Chessins
* Churchyard
* Cork Bark
* D. B. Cole
* Drake
* Dynasty
* Ed Wood
* Elsmo
* Emer I
* Emer II
* Emerald Prairie
* Frosty
* Garden City Clone
* Geisha
* Glory
* Golden Rey
* Hallelujah
* Hokkaido
* Jade Empress
* King's Choice
* Littleleaf
* Lois Hole
* Matthew
* Milliken
* Nire-keyaki
* Ohio
* Orange Ribbon
* Pathfinder
* Pendens
* Prairie Shade
* Prince Richard
* Red Fall
* Sabamiki
* Sagei
* Seiju
* Select 380
* Sempervirens
* Small Frye
* State Fair
* Stone's Dwarf
* Taiwan
* The Thinker
* Todd
* True Green
* UPMTF
* Ware's
* Yarralumla
* Yatsubusa
* Zettler
* Ulmus parvifolia f. lanceolata

European white elm|

* Aureovariegata
* Colorans
* Helena
* Ornata
* Pendula
* Punctata
* Urticifolia

Field elm|

* Albo-Dentata
* Amplifolia
* Argenteo-Variegata
* Atinia
* Atinia Pyramidalis
* Atinia Variegata
* Bea Schwarz
* Betulaefolia
* Biltii
* Christine Buisman
* Concavaefolia
* Coritana
* Cretensis
* Cucullata
* Cucullata Variegata
* Dehesa de Amaniel
* Dehesa de la Villa
* Dicksonii
* Dijkwel
* Erecta
* Folia Alba-Punctata
* Glandulosa
* Goodyeri
* Hoersholmiensis
* Holmstruph
* Hunnybunii
* Hunnybunii pseudo-Stricta
* Laciniata
* Lanuginosa
* Majadahonda
* Microphylla Pendula
* Microphylla Purpurea
* Microphylla Rubra
* Monumentalis
* Pendula
* Picturata
* Plotii
* Propendens
* Punctata
* Purpurascens
* Purpurea
* Retiro
* Reverti
* Rugosa
* Rueppellii
* Sarniensis
* Schuurhoek
* Silvery Gem
* Sowerbyi
* Stricta
* Suberosa
* Umbraculifera Gracilis
* Umbraculifera
* Viminalis
* Viminalis Aurea
* Viminalis Gracilis
* Viminalis Incisa
* Viminalis Marginata
* Viminalis Pendula
* Viminalis Pulverulenta
* Viminalis Stricta
* Virgata
* Webbiana

Japanese elm|

* Discovery
* Freedom
* Jacan
* JFS-Bieberich
* Mitsui Centennial
* Prospector
* Reperta
* Reseda
* Thomson
* Validation

Siberian elm|

* Ansaloni
* Aurea
* Aurescens
* Chinkota
* Dropmore
* Dwarf Weeper
* Green King
* Hansen
* Harbin
* Manchu
* Mauro
* Mr. Buzz
* Park Royal
* Pendula
* Pinnato-ramosa
* Poort Bulten
* Puszta
* Pyramidalis Fiorei
* Zhonghua Jinye

Winged elm|

* Lace Parasol

Wych elm|

* Albo-Variegata
* Australis
* Camperdownii
* Cebennensis
* Concavaefolia
* Cornuta
* Corylifolia Purpurea
* Corylifolia
* Fastigiata Macrophylla
* Fastigiata Stricta
* Fastigiata Variegata
* Firma
* Flava
* Gigantea
* Gittisham
* Grandidentata
* Holgeri
* Horizontalis
* Insularis
* Latifolia
* Latifolia Aurea
* Latifolia Aureo-Variegata
* Latifolia Nigricans
* Luteo Variegata
* Lutescens
* Macrophylla
* Maculata
* Minor
* Nana
* Nigra
* Nitida
* Oblongata
* Pendula Macrophylla
* Pendula Variegata
* Pyrenaica
* Spectabilis
* Superba
* Tomentosa

Hybrid cultivars|

* Androssowii
* Amsterdam
* Arno
* Cathedral
* Clusius
* Columella
* Den Haag
* Dodoens
* Escaillard
* Fiorente
* Frontier
* Fuente Umbria
* Homestead
* Karagatch
* Lobel
* Morfeo
* Morton
* Morton Glossy
* Morton Plainsman
* Morton Red Tip
* Morton Stalwart
* Nanguen
* New Horizon
* Patriot
* Plantyn
* Plinio
* Rebella
* Rebona
* Recerta
* Regal
* Repura
* Revera
* San Zanobi
* Sapporo Autumn Gold
* Sapporo Gold 2
* Stavast
* Toledo
* Urban
* Wanoux
* Wingham

Dutch elm|

* Alba
* Angustifolia
* Balder
* Belgica
* Blandford
* Canadian Giant
* Cicestria
* Cinerea
* Commelin
* Dampieri
* Dauvessei
* Daveyi
* Dovaei
* Dumont
* Elegantissima
* Eleganto-Variegata
* Etrusca
* Fastigiata
* Fjerrestad
* Folia Rhomboidea
* Freja
* Fulva
* Gaujardii
* Groeneveld
* Haarlemensis
* Klemmer
* Loke
* Macrophylla Aurea
* Major
* Microphylla
* Modiolina
* Muscaviensis
* Odin
* Pioneer
* Pitteurs
* Serpentina
* Smithii
* Superba
* Tricolor
* Tyr
* Vegeta
* Viminalis
* Viscosa
* Wentworthii Pendula
* Wredei
* Ypreau

U. × intermedia|

* Coolshade
* Fremont
* Improved Coolshade
* Lincoln
* Rosehill
* Willis

Unconfirmed derivation cultivars|

* aff. Plotii
* Acutifolia
* Ademuz
* Alata
* Alksuth
* Argenteo-Marginata
* Aspera
* Atropurpurea
* Australis
* Berardii
* Betulaefolia Nigrescens
* Crispa
* Crispa Aurea
* Crispa Pendula
* Densa
* Exoniensis
* Fastigiata Glabra
* Folia Aurea
* Folia Rubra
* Folia Variegata Pendula
* Gallica
* Glabra
* Globosa
* Hamburg
* Hertfordensis Angustifolia
* Hertfordensis Latifolia
* Hillieri
* Jalaica
* Jacqueline Hillier
* Kansas Hybrid
* Klemmer Blanc
* Koopmannii
* Lombartsii
* Louis van Houtte
* Marmorata
* Monstrosa
* Myrtifolia
* Myrtifolia Purpurea
* Nemoralis
* Nigrescens
* Planeroides
* Planifolia
* Purpurea
* Pyramidalis Bertini
* Ramulosa
* Rotundifolia
* Rubra
* Rufa
* Rugosa
* Scampstoniensis
* Sericea
* Tiliaefolia
* Tortuosa
* Turkestanica
* Variegata Nova
* Virens

Fossil elms|

* U. okanaganensis

Taxon identifiers

Ulmus thomasii|

* Wikidata: Q1147786
* Wikispecies: Ulmus thomasii
* APNI: 86894
* BOLD: 502125
* CoL: 7DFNX
* EoL: 594776
* EPPO: ULMTH
* FNA: 233501331
* FoAO2: Ulmus thomasii
* GBIF: 5361875
* GRIN: 101705
* iNaturalist: 54861
* IPNI: 294727-2
* IRMNG: 10590248
* ITIS: 19059
* IUCN: 61967392
* MichiganFlora: 2752
* NatureServe: 2.141424
* NBN: NBNSYS0000042217
* NCBI: 180953
* Open Tree of Life: 136509
* PfaF: Ulmus thomasii
* Plant List: kew-2448843
* PLANTS: ULTH
* POWO: urn:lsid:ipni.org:names:300247-2
* Tropicos: 33300073
* VASCAN: 9431
* WisFlora: 5301
* WFO: wfo-0000416829

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