| 词条 | Ulmus bergmanniana | |||
| 释义 |
|image = Ulmus bergmanniana leaves.jpg |image_caption = Ulmus bergmanniana, branchlet |genus = Ulmus |species = bergmanniana |authority = C.K.Schneid. }}Ulmus bergmanniana C.K.Schneid., commonly known as Bergmann's elm, is a deciduous tree found across much of China in forests at elevations of 1500–3000 m.[1] DescriptionThe tree is very closely related to the wych elm Ulmus glabra; it can reach a height of {{convert|26|m}} with a wide-spreading crown, and a trunk of about 0.9 m d.b.h.[2] The bark is longitudinally fissured, and varies in colour from greyish-white to dark grey. The pubescent leaves range from obovate to elliptic, less than {{convert|16|cm|abbr=on}} long, and bluish-green when mature.[3][4] The perfect, wind-pollinated apetalous flowers are produced on second-year shoots in February, followed by generally obovate samarae <30 mm long by 14 mm width, the centre of the seed about 7 mm from the slightly notched apex. Branchlets do not possess the corky wings characteristic of many other elm species. Pests and diseasesU. bergmanniana has a moderate resistance to Dutch elm disease; in trials [5] in Oklahoma it was also found to be eschewed by the elm leaf beetle Xanthogaleruca luteola , but further north at the Morton Arboretum was moderately to highly preferred by the insect. The species is also susceptible to the elm leafminer.[6]CultivationThe tree was introduced to the West in 1900. In trials in the USA it was found to propagate well, and also proved to be very winter hardy. The tree was one of 12 Chinese species under evaluation at the Morton Arboretum, Illinois, in 2009 by the late Dr George Ware.[7] There are no known cultivars of this taxon. Subspecies & varietiesTwo varieties are recognized: var. bergmanniana L.K.Fu, and var. lasiophylla C.K.Schneid.. EtymologyThe species was named by Camillo Karl Schneider for his friend Carl Bergmann, who assisted in indexing the work in which it was published.[8] Accessions
Nurseries
References1. ^{{cite web|url= http://eol.org/pages/2872452/details|title=Ulmus bergmanniana_EOL}} 2. ^Fu, L., 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. {{ISBN|1930723407}} 3. ^ 4. ^White, J. & More, D. (2003). Trees of Britain & Northern Europe. Cassell's, London. {{ISBN|0304361925}} 5. ^{{Cite web|url=http://www.sunshinenursery.com/survey.htm|access-date=17 July 2017|archiveurl=https://web.archive.org/web/20110719132152/http://www.sunshinenursery.com/survey.htm|title=Elm Leaf Beetle Survey|archive-date=2011-07-19}} 6. ^Grimshaw, J. & Bayton, R. (2009). New Trees - Recent Introductions to Cultivation. RBG Kew, London. {{ISBN|978-1-84246-173-0}} 7. ^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] 8. ^Schneider, C.K. (1906-1912). Illustriertes Handbuch der Laubholzkunde. Vol.2. p.902. Gustav Fischer Verlag, Jena. External links
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