• You are here:
• Full Key
• Woody plants
• Broad-leaved woody plants
• Betula nigra

Betula nigra — river birch

Facts

River birch is widely planted for its appealing, peeling bark and shiny, diamond-shaped leaves. Some trees may have naturalized in the wild from yards and gardens, but several populations in New England are native, and the species is listed as rare in New Hampshire and Massachusetts. A tree of floodplains and swampy bottomlands, this versatile species also grows well in drier soils.

Habitat

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

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

  Terminal bud

  there is no terminal bud on the branch

  Winter bud stalks

  the winter buds have no stalks

• Flowers

  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 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 position

  the inflorescences grow on the twigs

  Inflorescence type

  the inflorescence is an ament (catkin; slender, usually pendulous inflorescence with crowded unisexual flowers)

  Number of pistils

  1

  Ovary position

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

  Petal and sepal arrangement

  • the flower includes only one cycle of petals or sepals
  • the flower lacks sepals and petals

  Petal appearance

  NA

  Petal fusion

  NA

  Sepal cilia (Ilex)

  NA

  Sepal tip glands

  there are no glands at the tips of the sepal lobes

  Sepals fused only to sepals

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

  Stamen number

  1 or 2

  Stamen position relative to petals

  NA

  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)

  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

  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 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

  there is a noticeable powdery or waxy bloom on the underside of the leaf

  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

  • at least some of the hairs on the leaf blade have glands at their tips
  • the hairs on the leaf blade are different from the choices given

  Leaf blade length

  40–80 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)
  • the leaf blade is rhombic (roughly diamond-shaped)

  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 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

  30–60 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 has glands on the upper surface
  • 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
  • the leaf blade margin is serrulate (with forward-pointing) or denticulate (with outward-pointing) with tiny teeth

  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

  the plant has stipules

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Massachusetts
  • New Hampshire

  Specific habitat

  • forests
  • river or stream floodplains
  • shores of rivers or lakes

• 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
  • the bark of an adult plant is thin and smooth
  • 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
  • the twigs have hairs with glands at their tips

  Twig papillae (Vaccinium species only)

  NA

  Twig scales

  there are no scales on the twig surface

  Twig winter color

  • brown
  • gray
  • orange
  • purple
  • 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