''Ulmus'' × ''hollandica'' var. ''insularum'' was recognized as a biometrically distinct population of ''U.'' × ''hollandica'' endemic to all the

Channel Islands The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...

and the

Cotentin The Cotentin Peninsula (, ; nrf, Cotentîn ), also known as the Cherbourg Peninsula, is a peninsula in Normandy that forms part of the northwest coast of France. It extends north-westward into the English Channel, towards Great Britain. To its w ...

peninsula of France by Richens and Jeffers in 1975. The tree had been treated within ''U. montana'' (:''glabra'') until McClintock correctly assigned it to ''U. × hollandica''.McClintock, D. (1975). ''The wild flowers of Guernsey'', p.149. London.

Description

Var. ''insularum'' has an open canopy comprising irregular branching; the leaves are broadly

ovate Ovate may refer to: * Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ova ...

, < 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 Lamina may refer to: Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics * Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...

. Richens did not investigate the flowers and fruit.

Pests and diseases

The tree is very susceptible to

Dutch elm disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into Americas, America ...

Cultivation

The current status of the tree in the Channel Islands following the introduction of Dutch elm disease is not (2015) recorded.

References

{{DEFAULTSORT:Ulmus x hollandica var. insularum Ulmus hybrids Ulmus articles missing images Ulmus