• You are here:
• Simple Key
• Woody plants
• Broad-leaved woody plants
• Platanus occidentalis

Platanus occidentalis — American sycamore

Facts

American sycamore is a handsome tree with a patterned white-gray bark that flakes off to reveal a green inner bark. It can attain an enormous girth, especially in its native habitats in floodplains. One tree measured by George Washington was 13 feet (3.5m) in diameter. Old sycamores often have hollow trunks, which provide shelter to flocks of chimney swifts and even denning sites for black bear. Cross-sections of fat trunks were used as early cart wheels by pioneer settlers. Sycamore is also widely planted as a majestic street tree, although it is susceptible to injury from ozone and other pollutants.

Habitat

Floodplain (river or stream floodplains), shores of rivers or lakes, swamps

Characteristics

• Buds or leaf scars

  Bud position relative to scar

  the winter bud has a leaf scar partially or completely surrounding it

  Bud scale number

  there is one scale on the winter bud, and it covers the scale like a cap

  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

  Terminal bud

  there is no terminal bud on the branch

  Winter bud distribution

  the winter buds are distributed fairly evenly along the twig

  Winter bud scale hairs

  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 conical (cone-shaped)
  • the winter buds are ovoid (egg-shaped)

  Winter bud stalks

  the winter buds have no stalks

• Flowers

  Enlarged sterile flowers

  there are no enlarged sterile flowers on the plant

  Flower appearance

  the flowers appear at the same time as the leaves

  Flower petal color

  NA

  Flower symmetry

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

  Hairs on ovary (Amelanchier)

  NA

  Hypanthium present

  the flower does not have a hypanthium

  Inflorescence hairs

  there are hairs on some part of the inflorescence

  Inflorescence type

  • the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
  • the inflorescence has only one flower on it

  Number of pistils

  • 3
  • 4
  • 5
  • 6 or more

  Ovary position

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

  Petal and sepal arrangement

  the flower includes two cycles of petal- or sepal-like structures

  Petal appearance

  NA

  Petal fusion

  NA

  Sepal appearance

  the sepals resemble leaves 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

  • 3
  • 4
  • 5
  • 6
  • 7
  • 8

  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 tissue origin

  there are no flower parts that form part of the fruit

  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)
  • the fruit is an aggregate (composed of multiple fused ovaries from one flower)

  Nut with spines (Fagaceae)

  NA

  Wings on fruit

  there are no wings on the fruit

• 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

  Hairs on upper side of leaf blade

  the upper side of the leaf is fuzzy or hairy

  Leaf blade base shape

  • The base of the leaf blade is cordate (heart-shaped, with rounded lobes)
  • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
  • 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 symmetrical

  Leaf blade bloom

  the underside of the leaf has no noticeable bloom

  Leaf blade edges

  the edge of the leaf blade has lobes, or it has both teeth and lobes

  Leaf blade edges (Acer)

  NA

  Leaf blade flatness

  the leaf is flat (planar) at the edges

  Leaf blade hairs

  at least some of the hairs on the leaf blade are branched

  Leaf blade length

  50–200 mm

  Leaf blade scales

  there are no scales on the leaf blades

  Leaf blade shape

  the leaf blade is ovate (widest below the middle and broadly tapering at both ends)

  Leaf blade texture

  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 palmate (radiate out from the base, like a hand)

  Leaf blade veins

  the leaf blade has three or more main veins running from the base (or near the base) towards the tip

  Leaf blade width

  50–250 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 is serrate (with forward-pointing) or dentate (with outward-pointing) with medium-sized to coarse teeth

  Leaf teeth hairs (Carya)

  NA

  Leaf type

  the leaf blade is simple (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 (lobed or unlobed but not separated into leaflets

  Stipules

  the plant has stipules

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

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

  Specific habitat

  • 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 peels off easily or hangs off

  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 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

  Twig papillae (Vaccinium species only)

  NA

  Twig scales

  there are no scales on the twig surface

  Twig winter color

  • brown
  • gray
  • orange

  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