''Ulmus × intermedia'' Elowsky is a natural

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

elm Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...

occurring across

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

and several other

Midwestern states The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

, derived from the crossing of ''

Ulmus rubra ''Ulmus rubra'', the slippery elm, is a species of elm native to eastern North America. Other common names include red elm, gray elm, soft elm, moose elm, and Indian elm. Description ''Ulmus rubra'' is a medium-sized deciduous tree with a spre ...

'' and ''

Ulmus pumila ''Ulmus pumila'', the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm' ('' Ulmus parvifolia''). ''U. pumila'' has been widely cultivated throughout Asia, No ...

''. As Red Elm ''U. rubra'' is far less fertile, and highly susceptible to

Dutch elm disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into Americas, America ...

(:DED), it could eventually be hybridized out of existence by ''U. × intermedia''. Schlautman, B., Zalapa, J., & Brunet, J. (2012). Genotypic and phenotypic characterization of Ulmus pumila (Siberian elm), Ulmus rubra (Red elm) and their hybrids. ''Proc. Nebraska Acad. Sci. 2012''. 106–107. The hybrid was first reported from the wild in the Chicago region in 1950 and was provisionally named ''U.'' × ''notha'' Wilhelm & Ware in 1994. The

horticulture industry The horticulture industry embraces the production, processing and shipping of and the market for fruits and vegetables. As such it is a sector of agribusiness and industrialized agriculture. Industrialized horticulture sometimes also includes the ...

made a number of artificial crosses of the two species, such as 'Coolshade' and 'Fremont', in an attempt to create ornamental trees resistant to DED.

Description

''Ulmus × intermedia'' is significantly different from both parental species, except in biometrics such as leaf length to width ratios, number of teeth, petiole length, and pollen size. The leaves are 4.5–12 × 2.5–6 cm, petiole 0.3 × 1.2 cm, ovate to lanceolate, apex acuminate to acute, base oblique. The samarae are 11.5–21.0 × 10.0–20.0 mm, cream to white. Atypically, fertility of the hybrid seed is high, occasionally in excess of 90%,Kaul, R. B. (1995). Natural and fertile hybrids of the native red elm, Ulmus rubra, with the introduced Siberian elm, U. pumila, are now producing hybrid swarms in Nebraska. ''Proc. Nebraska Acad. Sci.'' 105: 28–29. while Collins found in artificial hybridization no reduction of fertility in the F1 or F2 generations.Collins, P. E. (1967). ''Hybridization studies in the genus Ulmus.'' Ph.D dissertation, Univ. of Minnesota, Minneapolis.

Pests and diseases

Morton Arboretum report the hybrid susceptible to DED and

Elm Yellows Elm yellows is a plant disease of elm trees that is spread by leafhoppers or by root grafts."Elm Yellows." Elmcare.Com. 19 Mar. 2008 . Elm yellows, also known as elm phloem necrosis, is very aggressive, with no known cure. Elm yellows occurs in th ...

(Elm phloem necrosis).

Cultivation

Specimens of unnamed ''Ulmus × intermedia'' ( = ''Ulmus × notha'') stand (2015) in

Morton Arboretum The Morton Arboretum, in Lisle, Illinois, United States, is a public garden, and outdoor museum with a library, herbarium, and program in tree research including the Center for Tree Science. Its grounds, covering 1,700 acres (6.9 square kilometres ...

, Illinois, received as ''Ulmus pumila'' from North Platte Agricultural Experiment Station, University of Nebraska.''U.'' × ''notha'', Morton Arboretum , vplants.org
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Cultivars

'Hamburg' may also belong to the ''Ulmus'' × ''intermedia'' group.''U. pumila'' x ''U. rubra'' 'Hamburg', in ''Handbuch der Ulmengewächse'', www.ulmen-handbuch.de
/ref>

References

External links

"Herbarium specimen 0030674MOR "
Morton Arboretum Herbarium. Sheet labelled ''U.'' × ''notha'' Wilhelm & Ware, Chicago region (1993) * ''Ulmus pumila'' x ''Ulmus rubra'', Richland Center, Wisconsin; Missouri Botanical Garden leaves specimen (2015) * ''Ulmus pumila'' x ''Ulmus rubra'', Richland Center, Wisconsin; Missouri Botanical Garden flowers specimen (2015) {{DEFAULTSORT:Ulmus intermedia

intermedia Intermedia is an art theory term coined in the mid-1960s by Fluxus artist Dick Higgins to describe various interdisciplinarity art activities that occur between genres, beginning in the 1960s. It was also used by John Brockman to refer to work ...

Plant nothospecies Ulmus articles missing images Ulmus hybrids