Ulmus × hollandica 'Viscosa' is probably one of a number of cultivars arising from the crossing of the Wych Elm

Wych Elm

Ulmus glabra, the Wych elm or Scots elm, has the widest range of the European elm species, from Ireland eastwards to the Urals, and from the Arctic Circle south to the mountains of the Peloponnese in Greece; it is also found in Iran...

 U. glabra with a variety of Field Elm

Field Elm

Ulmus minor Mill., the Field Elm, is by far the most polymorphic of the European species, although its taxonomy remains a matter of contention. Its natural range is predominantly south European, extending to Asia Minor; its northern outposts are the Baltic islands of Öland and Gotland, although it...

 U. minor. The tree was listed by Loddiges

Loddiges

The Loddiges family managed one of the most notable of the eighteenth and nineteenth century plant nurseries that traded in and introduced exotic plants, trees, shrubs, ferns, palms and orchids into European gardens....

, (Hackney

Hackney Central

Hackney Central is the central district of the London Borough of Hackney in London, England. It comprises the area roughly surrounding, and extending north from Mare Street. It is situated north east of Charing Cross...

, London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

) in his catalogue of 1836 and two years later by Loudon

John Claudius Loudon

John Claudius Loudon was a Scottish botanist, garden and cemetery designer, author and garden magazine editor.-Background:...

 in Arb. Frut. Brit. 3: 1378, 1838, as U. viscosa. An early specimen in the Herbarium Dumortier named U. viscosa Audibert was later sunk by Melville

Ronald Melville

Ronald Melville was an English botanist, based at the Royal Botanic Gardens Kew. He is chiefly remembered for his wartime research into rosehips as a source of vitamin C, prompted by the epidemic of scurvy amongst children owing to the reduced importation of fresh fruit...

 as U. × hollandica.

Description

'Viscosa' was distinguished by its large, deep-green leaves with anthocyanin

Anthocyanin

Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...

pigment.