The American elm is a large deciduous tree native to eastern North America, famed for its vase-shaped crown and severely affected in recent decades by Dutch elm disease.
| Kingdom | Plantae |
| Division | Magnoliophyta |
| Class | Magnoliopsida |
| Order | Rosales |
| Family | Ulmaceae |
| Genus | Ulmus |
| Species | Ulmus americana |
Before the arrival of Dutch elm disease, this tree would often exceed 30 metres in height, with a characteristic wide, open, vase-shaped crown. Its leaves are alternate, 7 to 20 cm long, with a doubly serrated margin and a slightly asymmetrical base.
Its fruits are flat samaras of about 2 cm, surrounded by a membranous wing that aids dispersal by air. It is a tetraploid tree, with twice the usual number of chromosomes for the genus, and reaches sexual maturity at around 150 years.
It is native to eastern North America, from Nova Scotia and southern Canada to Florida and central Texas. It is extremely cold-hardy, able to withstand winter temperatures as low as -42 °C.
It is the state tree of Massachusetts and North Dakota. Since the 20th century, the species has been decimated by Dutch elm disease, a fungal disease spread by beetles that now makes it uncommon for these trees to live beyond a century.
