Classification of Ulmus is based primarily on Whittemore et al 2021.
[1] Previous Ulmus classifications include Wiegrefe et al 1994,[2] and Melville & Heybroek 1971.
[3] Ulmus eolaciniata was moved from Ulmus to the new combination Rubus eolaciniata by Tanai and Wolfe in 1977.
[4]