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- Betula nigra
Betula nigra — river birch
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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
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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Characteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- New Hampshire
- Growth form
- the plant is a tree
- 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
- Leaf blade edges
- the edge of the leaf blade has teeth
- Leaf duration
- the leaves drop off in winter (or they wither but persist on the plant)
- armature on plant
- the plant does not have spines, prickles, or thorns
- Leaf blade length
- 40–80 mm
- Leaf blade width
- 30–60 mm
- Leaf stalk
- the leaves have leaf stalks
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- 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
- Twig winter color
-
- brown
- gray
- orange
- purple
- red
- 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
-
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)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- unranked (S-rank: SNR)
- Massachusetts
- uncommon (S-rank: S3)
- New Hampshire
- rare (S-rank: S2), threatened (code: T)
From Flora Novae Angliae dichotomous key
6. Betula nigra L. nC
river birch. CT, MA, NH. River banks, riparian forests, lake shores. Introduced to many locations but likely native to some sites in MA and NH, such as along the Merrimack River ( MA, NH) and several ponds in Essex County, MA. Reports of this species in VT (e.g., Seymour 1982) are based on a collection taken from a cultivated plant— Charette 2345 ( VT).
Native to North America?
Yes
Sometimes confused with
- Betula papyrifera:
- leaf blades ovate, petioles not tomentose, and body of samara not wider than individual wings (vs. B. nigra, with leaf blades rhombic, petioles tomentose, and body of samara wider than the individual wings).