Netleaf Hackberry, Western Hackberry: Celtis reticulata (Synonyms: Celtis douglasii, Celtis laevigata, Celtis laevigata var. reticulata, Celtis occidentalis var. reticulata, Celtis reticulata var. vestita) - Note: Now considered part of the Cannabaceae.
American Elm: Ulmus americana (Synonyms: Ulmus americana var. aspera, Ulmus americana var. floridana, Ulmus floridana)
Chinese Elm, Little-leaved Elm: Ulmus parvifolia
Dwarf Elm, Siberian Elm: Ulmus pumila (Synonyms: Ulmus campestris var. pumila, Ulmus manshurica, Ulmus turkestanica)