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- Juglans nigra
Juglans nigra — black walnut
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Facts
Black walnut is one of the most highly prized trees of the North American flora -- for its edible walnuts and its exceptionally beautiful wood with darkly patterned grain. It was a dominant and majestic canopy species of primeval midwestern and southeastern forests, attaing heights of 150 feet (50 m) or more. But clearing for agriculture and harvesting for making railroad ties, gunstocks, log cabins, cradles, veneer, and cabinets decimated the species. Its glossy, mostly hairless leaves and twigs with light-brown pith distinguish black walnut from other Juglans species. Chemicals exuded from its roots may inhibit the growth of other plants.
Habitat
Anthropogenic (man-made or disturbed habitats), forests, meadows and fields
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
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Growth form
- the plant is a tree
- Leaf type
- the leaf blade is compound (made up of two or more discrete 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
- 200–600 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
- Twig winter color
-
- brown
- gray
- red
- Bud scale number
- there are two scales on the winter bud, and their edges meet
-
Buds or leaf scars
- Bud scale number
- there are two scales on the winter bud, and their edges meet
- Bud scar shape (Fraxinus)
- NA
- Collateral buds
- there are no collateral buds on the sides of the branches
- Superposed buds
- there are no superposed buds on the branch
-
Flowers
- Carpels fused
- the carpels are fused to one another
- Enlarged sterile flowers
- there are no enlarged sterile flowers on the plant
- 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 type
-
- the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
- 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
- Petal appearance
- NA
- Petal fusion
- NA
- Sepal cilia (Ilex)
- NA
- Stamen number
- 13 or more
- Stamen position relative to petals
- NA
-
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 a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
- the fruit is a nut (dry and indehiscent, with a hard wall, usually containing only one seed and usually subtended by an involucre)
- 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 upper side of leaf blade
-
- the upper side of the leaf is fuzzy or hairy
- 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 truncate (ends abruptly in a more or less straight line as though cut off)
- 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
-
- NA
- at least some of the hairs on the leaf blade are branched
- at least some of the hairs on the leaf blade have glands at their tips
- Leaf blade length
- 200–600 mm
- Leaf blade scales
-
- there are no scales on the leaf blades
- there are scales on the leaf blades
- Leaf blade shape
- the leaf blade is oblong (rectangular but with rounded ends)
- Leaf blade texture
-
- the leaf blade is coriaceous (has a firm, leathery texture)
- the leaf blade is herbaceous (has a leafy texture)
- Leaf blade translucent dots
- there are no translucent dots on the leaf blade
- Leaf duration
- the leaves drop off in winter (or they wither but persist on the plant)
- 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 nectaries
- there are no nectaries on the leaf stalk
- 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 compound (made up of two or more discrete leaflets
- Leaves per node
- there is one leaf per node along the stem
- Specific leaf type
- the leaf is compound, with a single terminal leaflet and more than two additional leaflets
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- forests
- man-made or disturbed habitats
- meadows or fields
-
Scent
- Plant odor
-
- the plant does not have much of an odor, or it has an unpleasant or repellant odor
- the plant has a pleasantly aromatic 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
- Pith type
- the pith inside the twig is chambered (there are hollow sections with walls between them)
- Twig papillae (Vaccinium species only)
- NA
- 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 non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Connecticut
- unrankable (S-rank: SU)
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
3. Juglans nigra L. nC
black walnut. Wallia nigra (L.) Alef. • CT, MA, ME, NH, RI, VT. Roadsides, yards, field edges, deciduous forests. This species is certainly not native to most of New England; however, it is possibly native to some CT counties ( fide Dowhan 1979; including Litchfield County) and should receive conservation focus.
Native to North America?
Yes