Ulmus laciniata var. nikkoensis

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Ulmus laciniata var. nikkoensis
Ulmus laciniata v nikkoensis.jpg
Nikko Elm at the Morton Arboretum
Scientific classification edit
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Ulmaceae
Genus: Ulmus
Species:
Variety:
U. l. var. nikkoensis
Trinomial name
Ulmus laciniata var. nikkoensis

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.

Description[edit]

var. nikkoensis leaves

Var. 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 diseases[edit]

Heybroek found the tree provided 'relatively resistant' (to DED) progeny in the Dutch elm breeding programme.[1]

Cultivation[edit]

There are no known cultivars of this taxon, nor is it known to be in commerce beyond the United States.

Etymology[edit]

Var. nikkoensis is named for the Nikkō National Park near the city of Nikkō, 125 km north of Tokyo.

Accessions[edit]

North America
Europe

References[edit]

  1. ^ a b Heybroek, Hans M. (1981). "The Japanese elm species and their value for the Dutch elm breeding program" (PDF). Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, Winnipeg, Manitoba: 78–90.
  2. ^ Hans, A. S. (1981). "Compatibility and Crossability Studies in Ulmus". Silvae Genetica. 30: 4–5.
  3. ^ J, Ohwi (1965). Flora of Japan. Smithsonian Institution.
  4. ^ J., Grimshaw; Bayton, R. "New Trees - Recent Introductions to Cultivation". Royal Botanic Gardens, Kew, London.
  5. ^ "Collectionsgarden_Plant Search". Archived from the original on October 25, 2007.
  6. ^ "Nikko Elm - Ulmus laciniata var. 'nikkoensis'".