Ulmus microcarpa
{{Short description|Species of tree}}
{{Speciesbox
|image = U. microcarpa foliage 1.jpg
|image_caption = Juvenile U. microcarpa foliage, Great Fontley UK
|genus = Ulmus
|species = microcarpa
|authority = L. K. Fu
}}
Ulmus microcarpa was named and first described by the Chinese botanist L. K. Fu, who discovered the tree in the Chayu broad-leaved forests of south-eastern Xizang at altitudes of around 2800 m during the 1973 Qinghai - Tibet Expedition.Fu, L. K. (1979). Chinese plant database and catalogue - Ulmus microcarpa. Acta Phytotaxonomica Sinica 17(1): 48–49, pl. 2, f. 5–8, 48 1979, Beijing, China Unlike the majority of Tibet, the Chayu region has a subtropical highland climate featuring warm, wet, summers and mild, dry, winters (avg. annual rainfall 807 mm). Commonly known as the Tibetan Elm, the tree was introduced to the United States in 2006, and the UK in 2013; it remains one of the rarest species of elm in cultivation.
Description
U. microcarpa can reach a height of 30 m in the wild, the trunk < 80 cm d.b.h. The large oblong to elliptic leaves are 8.5–17 cm long by 5–8 cm broad with 5 mm petioles, likened by Fu to those of U. wallichiana and U. bergmanniana var. lasiophylla, but much smaller on juvenile plants. As its specific epithet implies, the suborbicular, glabrous samarae are small, 7–8 mm long by 7–8 mm wide, the seed at the centre. Ploidy: 2n = 28.Fu, L. K., Xin, Y. & Whittemore, A. (2002). Ulmaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 5 (Ulmaceae through Basellaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA [http://flora.huh.harvard.edu/china/PDF/PDF05/Ulmus.pdf]
Growth in the UK has been slow, the branches on juvenile trees increasing in length by no more than 10–12 cm per annum on moist, fertile soil. The species is the first to leaf in spring in the UK, and the first to defoliate in autumn, usually by late September.Brookes, A. (2017). Great Fontley Elm Trial Report 2017. Butterfly Conservation, Lulworth, UK.
File: U. microcarpa foliage detail.jpg|Foliage detail, Great Fontley, UK
File:Ulmus microcarpa, last and previous year's growth.jpg|Last and previous year's branchlet growth
File:Ulmus microcarpa emergent leaves March week 1.jpg|Leaf buds, March week 1
Pests and diseases
No information available; U. microcarpa was not known in the United States when the majority of Asiatic elms were screened for resistance to Dutch elm disease by the late George Ware at the Morton Arboretum, Illinois, in the early 1990s.Ware, G. (1995). Little known elms from China: landscape tree possibilities. Journal of Arboriculture. 21(6), 284–288. November 1995.
Cultivation
U. microcarpa is very rare in cultivation outside China, and accessions are (2019) restricted to two arboreta in the United States and four in the UK. The tree was one of 12 Chinese species under evaluation at the Morton Arboretum, Illinois, in 2009 by the late Dr George Ware.Dirr, M. (2009). 'Future Tree Selections'. Western, Spring 2009, p.8. Western Nursery & Landscape Association, St Joseph, Missouri.[https://www.yumpu.com/en/document/view/52250445/dr-michael-a-dirr-offering-future-tree-selections/4]
Accessions
;North America
- Brenton Arboretum, US. Acc. no. 06–035; from the Morton Arboretum (see below).{{Citation needed|date=February 2025}}
- Morton Arboretum, US. Acc. nos. 362–2006, 588–2006, from seed wild collected in Tibet[https://www.publicgardens.org/wp-content/uploads/2018/11/PCN-Morton_Ulmus.pdf Collection holdings], [https://www.publicgardens.org/napcc_collection/ulmus/ Ulmus], Morton Arboretum, American Public Gardens Association by the Chinese Academy of Forestry, Research Institute of Forestry Tibet Autonomous Region, China.{{Citation needed|date=February 2025}}
;Europe
- Grange Farm Arboretum, Lincolnshire, UK. Rooted cuttings from Brenton Arboretum, acquired 2013. Acc. no. 1076.{{Citation needed|date=February 2025}}
- Royal Botanic Garden Edinburgh, UK. One small rooted cutting acquired 2014. Acc. no. 20141572.Royal Botanic Garden Edinburgh. (2017). List of Living Accessions: Ulmus [http://data.rbge.org.uk/search/livingcollection/?eti=Ulmus&cfg=livcol.cfg&start=20]
- Sir Harold Hillier Gardens, Ampfield, Hampshire, UK. Rooted cutting in propagation unit (2018), acc. no. 2017.0196{{Citation needed|date=February 2025}}
- Wijdemeren City Council, Netherlands. 2 trees planted 2019 cemetery Hornhof, Nederhorst den Berg.{{Citation needed|date=February 2025}}
References
{{Reflist}}
External links
- [http://ppbc.iplant.cn/sp/222471 Photographs labelled U. microcarpa on Plant Photo Bank of China, ppbc.iplant]
- [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242414824 efloras.org: U. microcarpa description]
- [http://www.efloras.org/object_page.aspx?object_id=50116&flora_id=2 efloras.org: U. microcarpa leaves and fruit illustration, figures 4 to 7]
{{Elm species, varieties, hybrids, hybrid cultivars and species cultivars |state=collapsed}}
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Category:Elm species and varieties