| 词条 | Ulmus laciniata var. nikkoensis |
| 释义 |
| image = Ulmus laciniata v nikkoensis.jpg | image_caption = Nikko Elm at the Morton Arboretum | genus = Ulmus | species = laciniata | varietas = nikkoensis | authority = Rehder }}Ulmus laciniata var. nikkoensis Rehder, the Nikko elm, was discovered as a seedling near Lake Chūzenji, near Nikkō, Japan, and obtained by the Arnold Arboretum in 1905.[1] The taxonomy of the tree remains a matter of contention, and has been considered possibly a hybrid of U. laciniata and U. davidiana var. japonica. However, in crossability experiments at the Arnold Arboretum in the 1970s, U. laciniata, a protogynous species, was found to be incompatible with U. davidiana var. japonica, which is protandrous.[2] Significantly, the variety was not recognized by Ohwi,[3] though his reasons are not clear. DescriptionVar. nikkoensis is a small tree; the specimen at the Morton Arboretum likened to a cherry tree.[4] The tree is chiefly distinguished by leaves which are red on emergence, and toothed but not lobed as in the species. The perfect apetalous wind-pollinated flowers appear in March in England. Pests and diseasesHeybroek found the tree provided 'relatively resistant' (to DED) progeny in the Dutch elm breeding programme.[1]CultivationThere are no known cultivars of this taxon, nor is it known to be in commerce beyond the United States. EtymologyVar. nikkoensis is named for the Nikkō National Park near the city of Nikkō, 125 km north of Tokyo. Accessions
References1. ^1 {{cite journal | last = Heybroek | first=Hans M.|journal = Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, Winnipeg, Manitoba|title = The Japanese elm species and their value for the Dutch elm breeding program|pages = 78–90|date=1981|url=http://krishikosh.egranth.ac.in/bitstream/1/2055474/1/MPKV-1936.pdf}} {{Elm species, varieties, hybrids, hybrid cultivars and species cultivars |state=collapsed}}{{Taxonbar|from=Q7879495}}2. ^{{cite journal|last=Hans|first=A. S.|year=1981|title=Compatibility and Crossability Studies in Ulmus|journal=Silvae Genetica|volume= 30|pages=4–5}} 3. ^{{cite book|first=Ohwi|last= J|year=1965|url=https://books.google.com/books?id=aMjXCF4rmDUC&pg=PA779&lpg=PA779&dq=Ohwi,+J.+(1965)+Flora+of+Japan&source=bl&ots=CbgwU5Fq61&sig=FK4tmunt4f1DUVm7iRHPj71J6eQ&hl=en&sa=X&ei=yng8UvCYBc-qrAfuuIHwAQ&ved=0CC0Q6AEwAQ#v=onepage&q=Ohwi%2C%20J.%20(1965)%20Flora%20of%20Japan&f=false|title=Flora of Japan|publisher=Smithsonian Institution}} 4. ^{{cite web|first1=Grimshaw|last1= J.|last2= Bayton |first2= R.|title= New Trees - Recent Introductions to Cultivation |publisher=Royal Botanic Gardens, Kew, London|url=https://www.amazon.com/New-Trees-Recent-Introductions-Cultivation/dp/1842461737}} 5. ^{{cite web|url=http://www.dawesarb.org/collectionsgardens/plant-search.asp |title=Collectionsgarden_Plant Search |deadurl=yes |archiveurl=https://web.archive.org/web/20071025005915/http://www.dawesarb.org/collectionsgardens/plant-search.asp |archivedate=October 25, 2007 }} 6. ^{{cite web|url= http://www.cirrusimage.com/tree_Nikko_Elm.htm|title= Nikko Elm - Ulmus laciniata var. 'nikkoensis'}} 6 : Ulmus|Flora of Japan|Trees of Japan|Trees of Asia|Ulmus articles with images|Elm species and varieties |
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