Ulmus elliptica

Ulmus elliptica Koch (named for the elliptic samara) is a disputed species of elm, native to the Caucasus, where Koch reported (1849, 1872) that it formed extensive woods, and ranging north to southern Ukraine. The tree reminded Koch of the elm then called Ulmus major Smith, except in its samara. Others thought it closely related to U. glabra, but to resemble U. rubra in its samara (see Description below). Many authorities consider U. elliptica Koch just a regional form of U. glabra, though Henry, Bean and Krüssman list the Caucasus tree as a species in its own right. U. elliptica Koch is likewise distinguished from U. scabra Mill. [:U. glabra Huds.] in some Armenian and Russian plant lists. For a time, the Späth nursery, Berlin, distributed a disputed cultivar, U. Heyderi, as a synonym of U. elliptica Koch (see Cultivation below)....read more on Wikipedia.