| Ulmus laciniata | |
|---|---|
| Ulmus laciniata leaves | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Rosales |
| Family: | Ulmaceae |
| Genus: | Ulmus |
| Species: | U. laciniata |
| Binomial name | |
| Ulmus laciniata (Trautv.) Mayr |
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| Synonyms | |
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Ulmus laciniata (Trautv.) Mayr, known variously as the Manchurian, Cut-leaf, or Lobed Elm, is a deciduous tree native to the humid ravine forests of Japan, Korea, northern China, eastern Siberia and Sakhalin, growing alongside Cerciphyllum japonicum, Aesculus turbinata, and Pterocarya rhoifolia [1][2][3], at elevations between 700 m and 2200 m, though sometimes lower in more northern latitudes, notably in Hokkaido, eastern Siberia and Sakhalin.
The tree is similar to the Wych Elm Ulmus glabra, and was originally treated as such by Houtzagers and Augustine Henry, but later accorded species status of its own largely by reason of the enormous disjunction in their respective areas; U. glabra extending across Europe as far as the Urals, several thousand kilometres from U. laciniata in the Far East.
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Ulmus laciniata is chiefly distinguished by its leaves, often regularly incised to form between three and seven apical lobes, giving rise to its common synonym, the Cut-leaf Elm [3]. The tree can reach a height of 27 m, although the trunk rarely exceeds 0.5 m d.b.h. The bark is dark, grey brown and exfoliates in flakes. The branchlets are unwinged. The laciniate leaves are usually obtriangular, < 18 cm in length. The perfect wind-pollinated apetalous flowers are produced on second-year shoots in April (March in England), followed by elliptic < 20 mm × 14 mm samarae in May [4][5][6].
Natural populations of U. laciniata have only a marginal resistance to Dutch elm disease, rated 2 out of 5,[7] below that of the Japanese Elm [8]. Moreover, in trials in Italy and the USA [4], U. laciniata was severely damaged by elm leaf beetles Xanthogaleruca luteola, indeed in Italy chemical controls were necessary to ensure the tree's survival, unlike its compatriots U. parvifolia and U. davidiana var. japonica which survived unscathed. The species is also susceptible to Elm Yellows.[9].
The species was introduced to the West in 1905, but remains uncommon in cultivation. A specimen at the Ryston Hall, Norfolk, arboretum, obtained from the Leon Chenault[5] nursery in Orléans[10], was killed by the earlier strain of Dutch elm disease prevalent in the 1930s. The tree was comprehensively evaluated in the Netherlands in the 1950s as a potential source of anti-fungal genes for use in the Dutch elm hybridization programme, but was found intolerant of all but the most sheltered and humid conditions [8]. Trees planted at the Sir Harold Hillier Gardens (sole accession died 2007) and as part of Butterfly Conservation's elm trials at Great Fontley Farm, Fareham, England, have confirmed the Dutch assessment [11].
Trees grown from seed commence flowering in their eighth year. The Dutch elm breeding programme revealed that the tree has a relatively high degree (39 % seed viability) of self-fertility [12]. The species is very difficult to propagate from hardwood cuttings, even under mist, often rooting but failing to develop foliage.
There are no known cultivars of this taxon, nor is it known to be in commerce beyond the USA.
A variety was recognized by Rehder: Ulmus laciniata var. nikkoensis - the Nikko Elm.
Several hybrid cultivars were raised as part of the Dutch elm breeding programme at Wageningen (Heybroek, 1993), crossing the species with hybrids of U. wallichiana and U. minor to produce Clone no. 560, which in turn was crossed with Clone 720 (itself a complex cross involving U. glabra, U. minor, U. wallichiana, and U. pumila) to produce Clone 1234. None of these clones has been commercially released.