Ulmus americana, U. rubra, U. thomasii, U. alata, U. crassifolia, U. serotina US: elm, American e., slippery e., brown e., rock e., winged e.,cedar e., September e. UK: elm FR: orme DE: Ulme IT: olmo VL: iepen, Amerikaans i., soft elm, gray (grey) elm, white elm, water elm, red elm, slippery elm, Canadees iepen, rock elm NL: olmen
Elm
Six species of elm grow in the eastern United States: American (Ulmus americana), slippery (U. rubra), rock (U. thoma‑ sii), winged (U. alata), cedar (U. crassifolia), and September (U. serotina) elm. American elm is also known as white elm, slippery elm as red elm, rock elm as cork elm, and winged elm as wahoo. American elm is threatened by two diseases, Dutch Elm disease and phloem necrosis, which have killed hundreds of thousands of trees.