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• Ulmaceae
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• Ulmus americana

Ulmus americana — American elm

Facts

With its majestic, vase-shaped form accentuated by long, drooping branches, American elm is one of New England's most beautiful trees and was once a ubiquitous and monumental street tree in most towns. However, Dutch elm disease (a fungus introduced in imported logs from Europe in 1930) has decimated the species and large, mature individuals are now rare. Its wood has a high moisture content and its interlocking grain is difficult to split, making it useless for firewood and challenging to use for woodworking except for veneer and manufacturing hockey sticks and boxes.

Habitat

Anthropogenic (man-made or disturbed habitats), floodplain (river or stream floodplains), forests, meadows and fields, shores of rivers or lakes, swamps

Characteristics

• Buds or leaf scars

  Bud scale number

  there are three or more scales on the winter bud, and they overlap like shingles, with one edge covered and the other edge exposed

  Bud scar shape (Fraxinus)

  NA

  Collateral buds

  there are no collateral buds on the sides of the branches

  Leaf scar arrangement

  there is one leaf scar per node on the stem or twig

  Superposed buds

  there are no superposed buds on the branch

  Winter bud distribution

  the winter buds are distributed fairly evenly along the twig

  Winter bud scale hairs

  • the winter bud scales are hairy
  • the winter bud scales have no hairs on them

  Winter bud scales

  the winter bud is perulate (partially or completely covered with one or more scales)

  Winter bud shape

  the winter buds are ovoid (egg-shaped)

  Winter bud stalks

  • the winter buds have no stalks
  • the winter buds have short stalks

• Flowers

  Anther color

  there is a noticeable pink, reddish or purplish tint to the anthers

  Carpels fused

  the carpels are fused to one another

  Enlarged sterile flowers

  there are no enlarged sterile flowers on the plant

  Flower appearance

  the flowers appear before the leaves

  Flower petal color

  • red
  • yellow or green

  Flower symmetry

  there are two or more ways to evenly divide the flower (the flower is radially symmetrical)

  Hairs on ovary (Amelanchier)

  NA

  Inflorescence position

  the inflorescences grow on older branches

  Inflorescence type

  the inflorescence is a fascicle (compact cluster of flowers)

  Number of pistils

  1

  Ovary position

  the ovary is above the point of petal and/or sepal attachment

  Petal and sepal arrangement

  the flower includes only one cycle of petals or sepals

  Petal appearance

  the petals are thin and delicate, and pigmented (colored other than green or brown)

  Petal fusion

  the perianth parts are fused to form a tube, cup, or bell shape

  Sepal appearance

  the sepals resemble petals in color and texture

  Sepal cilia (Ilex)

  NA

  Sepal tip glands

  there are no glands at the tips of the sepal lobes

  Sepals fused only to sepals

  the sepals are fused to each other (not other flower parts), at least near their bases

  Stamen number

  • 7
  • 8
  • 9

  Stamen position relative to petals

  the stamens are lined up with the sepals (antesepalous)

  Stamens fused

  the stamens are not fused to one another

• Fruits or seeds

  Berry color

  NA

  Fruit type (general)

  the fruit is dry but does not split open when ripe

  Fruit type (specific)

  the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)

  Nut with spines (Fagaceae)

  NA

  Wings on fruit

  the fruit has one or more wings on it

• Glands or sap

  Sap color

  the sap is clear and watery

  Stalked glands on fruit (Rosa)

  NA

• Growth form

  Growth form

  the plant is a tree

• Leaves

  Hairs on underside of leaf blade

  • the underside of the leaf has hairs on it
  • the underside of the leaf has no hairs

  Hairs on upper side of leaf blade

  the upper side of the leaf is not hairy, or has very few hairs

  Leaf blade base shape

  • The base of the leaf blade is cordate (heart-shaped, with rounded lobes)
  • the base of the leaf blade is rounded
  • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)

  Leaf blade base symmetry

  the leaf blade base is asymmetrical

  Leaf blade bloom

  the underside of the leaf has no noticeable bloom

  Leaf blade edges

  the edge of the leaf blade has teeth

  Leaf blade edges (Acer)

  NA

  Leaf blade flatness

  the leaf is flat (planar) at the edges

  Leaf blade hairs

  the hairs on the leaf blade are different from the choices given

  Leaf blade length

  70–140 mm

  Leaf blade scales

  there are no scales on the leaf blades

  Leaf blade shape

  • the leaf blade is elliptic (widest near the middle and tapering at both ends)
  • the leaf blade is oblong (rectangular but with rounded ends)
  • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
  • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)

  Leaf blade texture

  • the leaf blade is chartaceous (thin and dry like paper)
  • the leaf blade is herbaceous (has a leafy texture)

  Leaf blade translucent dots

  there are no translucent dots on the leaf blade

  Leaf blade vein pattern

  the main veins of the leaf blade are pinnate (the secondary veins branch off at intervals from the main central vein) and non-arcuate (not arched towards the leaf tip)

  Leaf blade veins

  the leaf blade has one main vein running from the base toward the tip

  Leaf blade width

  30–70 mm

  Leaf duration

  the leaves drop off in winter (or they wither but persist on the plant)

  Leaf form

  the plant is broad-leaved (with broadly flattened leaf blades)

  Leaf lobe tips (Quercus)

  NA

  Leaf midrib glands

  the midrib of the leaf blade lacks glands on the upper surface

  Leaf stalk

  the leaves have leaf stalks

  Leaf stalk attachment to leaf

  the petiole attaches at the basal margin of the leaf blade

  Leaf stalk nectaries

  there are no nectaries on the leaf stalk

  Leaf stalk shape

  the leaf stalk is not flattened

  Leaf teeth

  the leaf blade margin has teeth, which themselves have smaller teeth on them

  Leaf teeth hairs (Carya)

  NA

  Leaf type

  the leaf blade is simple (i.e., lobed or unlobed but not separated into leaflets)

  Leaves per node

  there is one leaf per node along the stem

  Specific leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

  Stipules

  there are no stipules on the plant, or they fall off as the leaf expands

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • forests
  • man-made or disturbed habitats
  • meadows or fields
  • river or stream floodplains
  • shores of rivers or lakes
  • swamps

• Scent

  Plant odor

  the plant does not have much of an odor, or it has an unpleasant or repellant odor

• Stem, shoot, branch

  Aerial roots

  the plant has no aerial roots

  Bark texture

  the bark of an adult plant is ridged or plated

  Branch brittleness (willows only)

  NA

  Branch cross-section

  the branch is circular in cross-section, or it has five or more sides, so that there are no sharp angles

  First-year cane (Rubus)

  NA

  Lenticels on twigs

  there are clearly lenticels on the twigs

  Short shoots

  there are no peg- or knob-like shoots present

  Twig bloom

  there is no bloom on the twig

  Twig hairs

  • the twigs have few or no hairs on them
  • the twigs have hairs, but the hairs do not have glands

  Twig papillae (Vaccinium species only)

  NA

  Twig scales

  there are no scales on the twig surface

  Twig winter color

  • brown
  • gray
  • red

  Wings on branch

  the branch does not have wings on it

  armature on plant

  the plant does not have spines, prickles, or thorns

Wetland status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae