American elm
Ulmus americana L.
  • LEAVES: deciduous, alternate, simple; blades 4-6" long by 1-3" wide, oblong-obovate to elliptical, tips acuminate, bases asymmetrical, margins doubly serrate; smooth to slightly scabrous above (sometimes harshly scabrous on seedling/saplings and stump sprouts)
  • FLOWER: bisexual, small and inconspicuous, corolla absent, flowering very early, often in January, before leaves erupt, long pedicelled, fascicles of 3 or 4
  • FRUIT: oval-shaped samara with seed-bearing portion surrounded by wing, to ca. 0.4” long; wing deeply notched at apex, margin ciliate; fruit maturing in February-March
  • TWIGS: slender, with zigzag pattern, shoots of the season pubescent at first, the hairs soon sloughing, older twigs slender, not winged, brown or grayish brown; terminal winter buds absent, lateral buds ovoid or acute, but not sharp-pointed, glabrous and chestnut brown, bud scales glabrous or slightly pubescent
  • BARK: grayish brown, furrowed and ridged, sloughing is flakes or scales from ridges
  • FORM: long lived (to 300 years), large tree, to 100’ tall and 3-4’ dbh, base of trunk strongly fluted on wetter sites; crown urn-shaped when open-grown
  • HABITAT: bottomland hardwood forests, rich soil mesic upland hardwood forest; widely planted as ornamental
  • WETLAND DESIGNATION: Facultative (FAC): Occurs in wetlands or non-wetlands of the Atlantic and Gulf Coast Plain Region
  • RANGE: eastern U.S., extending into Canada [USGS Range Map]
  • USES: high quality wood for furniture, pulp, veneer (interlocking grain makes it difficult to work); very susceptible (more so than other elms) to Dutch elm disease (multiple insect vectors), caused by an imported fungus which killed many trees during the second half of the 20th century. Imported on log shipped to Ohio from France in 1931. By the 1980s Dutch elm disease had killed ca. 77 million trees. Various resistant cultivars have been developed and released.
  • WILDLIFE: samaras eaten by birds and squirrels; stump sprouts can be heavily browsed by whitetail deer following logging
  • Best Recognition Features:
    1. leaf margin doubly-serrate, base asymmetrical, apex acuminate
    2. fluted trunk in wet areas
    3. bark flaky-scaly, grayish brown
    4. lateral buds pointed, chestnut brown, scales glabrous

    Slippery elm (Ulmus rubra Muhl.) is similar to American elm. Slippery elm leaves are scabrous even on mature trees, lateral leaf veins typically fork near the leaf margin, the bark is brown to reddish, lateral buds are reddish, blunt, scales pubescent, twigs are roughened by persistent bases of hairs, and the samara is suborbicular and margin not ciliate. Slippery elm is relatively rare in Louisiana, with bona fide records from salt dome hardwood forests and southern mesophytic hardwood forests (Tunica Hills).
    [USGS Range Map]

    winged elm (Ulmus alata) leaves are smaller, and often have corky ridges on the twigs