Ulmus × hollandica var. insularum was recognized as a biometrically distinct population of U. × hollandica endemic to all the Channel Islands and the Cotentin peninsula of France by Richens and Jeffers in 1975.[1] The tree had been treated within U. montana (:glabra) until McClintock correctly assigned it to U. × hollandica.[2]
| Ulmus × hollandica var. insularum | |
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| Variety: | U. × hollandica var. insularum
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| Trinomial name | |
| Ulmus × hollandica var. insularum Richens
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Description edit
Var. insularum has an open canopy comprising irregular branching; the leaves are broadly ovate, < 8.5 cm long by 6 cm broad. The tree is distinguished from U. × hollandica and its most common cultivar, 'Vegeta', the Huntingdon Elm, by its longer (8–12 mm) petiole, greater foliar asymmetry, and more extensive axillary tufts on the lower surface of the lamina. Richens did not investigate the flowers and fruit.
Pests and diseases edit
The tree is very susceptible to Dutch elm disease.
Cultivation edit
The current status of the tree in the Channel Islands following the introduction of Dutch elm disease is not (2015) recorded.
References edit
- ^ Richens, Richard Hook (1984). "Ulmus × hollandica Miller var. insularum Richens, var. nov" (PDF). Watsonia. 15: 105–108.
- ^ McClintock, D. (1975). The wild flowers of Guernsey, p.149. London.