X-Nico

Ulmus 'Columella'

Clone FL 666 (Heybroek's 405* × 'Columella'), Istituto per la Protezione delle Piante, Florence.

Ulmus 'Homestead'

The cultivar arose from a 1970 crossing of the Siberian Elm Ulmus pumila (female parent) with the hybrid N 215 ('Commelin' × (U. pumila var. arborea × U. minor 'Hoersholmiensis')), the latter grown from seed sent in 1960 to the University of Wisconsin-Madison elm breeding team by Hans Heybroek of the De Dorschkamp Research Institute in the Netherlands.

Ulmus 'Lobel'

'Lobel' was introduced to North America in 1991 when Heybroek donated material to the North Central Regional PI Station, Iowa State University, but the tree is not known to have been commercially released there.

Ulmus 'Pitteurs Pendula'

However, Hans M. Heybroek, erstwhile head of the elm breeding programme at the de Dorschkamp Research Institute for Forestry & Landscape Planning at Wageningen, identified the tree as Zelkova × verschaffeltii.

see also