The elm cultivar Ulmus 'Klemmer Blanc' was described by Feneau in Bulletin de la Société centrale forestière de Belgique (1902) as an intermediate between 'Klemmer' and 'Belgica', the Belgian Elm.
[1][2] The leaves are smaller than 'Klemmer', and the trees do not produce root suckers.
Moreover, the timber is white and softer than 'Klemmer'.
[3] No specimens are known to survive.