Ulmus 'Nanguen' (selling name Lutèce) is a complex fourth generation Dutch hybrid cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen.

[2] Originally identified as clone '812', Lutèce was not promoted by the Dutch owing to unfounded fears that it may prove susceptible to coral spot fungus (Nectria cinnabarina).

[7] Quick growing on moist, well-drained soils, increasing in height by an average of 80 cm per annum, the tree commences flowering in late March when aged seven years.

[13] Lutèce was introduced to the UK by the Hampshire & Isle of Wight Branch, Butterfly Conservation, in 2001, as part of its assessment of DED-resistant cultivars as potential hosts of the endangered White-letter Hairstreak.

[14] Among urban introductions in the UK are three specimens, planted in 2014, at the west end of Broad Walk, Christ Church Meadow, Oxford,[14][15] and three in Princes Street Gardens, Edinburgh.

[2] The flowering period of Lutèce coincides in part with that of field elm, and the seeds harvested have produced viable seedlings, though possibly selfed.

This was confirmed in 2015 with the discovery of the butterfly breeding on specimens planted in 2003 at Towngate, Newport, Isle of Wight (see photo 5 in Gallery) and at Great Fontley in 2021 .