| Ulmus pumila var. arborea | |
|---|---|
| var. arborea, Netherlands. Photo: Ronnie Nijboer, Bonte Hoek kwekerijen | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Rosales |
| Family: | Ulmaceae |
| Genus: | Ulmus |
| Species: | U. pumila |
| Trinomial name | |
| Ulmus pumila L. var. arborea Litv. |
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| Synonyms | |
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Ulmus pumila var. arborea, sometimes called the Turkestan elm, is endemic to western Siberia and Turkestan. The tree was introduced to Europe by Georg Dieck in 1894 as U. pinnato-ramosa.
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The tree is distinguished from U. pumila var. pumila by its greater height and more slender leaves.[1][2] The leaves have pinnate venation, are 4–7 cm in length, ovate-lanceolate, double-toothed and finely pointed. Var. arborea grows very vigorously, and can ultimately make a large tree[3]. The tree has a straggling, untidy habit, producing long shoots 0.60–0.95 m in length.[4]
A specimen at the Ryston Hall [3], Norfolk, UK, arboretum, obtained from the Späth nursery in Berlin before 1914[5], was killed by the earlier strain of Dutch elm disease prevalent in the 1930s.
Originally raised by Späth from seed from Turkestan, the tree is still occasionally found in Europe and North America. Introduced to Croatia from Italy, it can be found in many places along the Croatian littoral.[6]
A tree labelled Ulmus turkestanica in the Royal Botanic Garden, Edinburgh, was killed by Dutch Elm Disease in the 1990s; in neither foliage nor form did it resemble the nearby elm, still surviving, labelled Ulmus pinnato-ramosa, a synonym of Ulmus pumila var. arborea [7] (see Notable Trees below).
Also introduced to Australia, the tree was listed by nurseries there (as U. turkestanica) in the early 20th century, but it is not known whether it still survives in that country.
There are no known cultivars of this taxon, nor is it known to remain in commerce.
The USA national champion tree in Detroit, Michigan, is 45 m tall, with a crown of 34 m width [4]. A tree planted in 1902 survives (2011) at the Royal Botanic Garden Edinburgh.[8]