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Rhamnus alnifolia — alder-leaved buckthorn

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Facts

Alder-leaved buckthorn is a native shrub that tends to grow in calcareous wetlands (fens) in western and northern New England. It differs from all other members of the genus Rhamnus in our area by having flowers with five sepals, no petals, and five stamens (the other species have four of each). The flowers attract butterflies and the bright red fruits attract birds.

Habitat

Fens, swamps

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Growth form
the plant is a shrub (i.e., a woody plant with several stems growing from the base)
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
40–100 mm
Leaf stalk
the leaves have leaf stalks
Fruit type (general)
the fruit is fleshy
Bark texture
the bark of an adult plant is thin and smooth
Twig winter color
  • brown
  • 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
Show all 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
    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 has a hypanthium
    Inflorescence type
    • the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
    • the inflorescence is an umbel (with an axis so short it appears the flowers all originate from the same point)
    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 two cycles of petal- or sepal-like structures
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal fusion
    the perianth parts are separate
    Sepal cilia (Ilex)
    NA
    Stamen number
    5
    Stamen position relative to petals
    the stamens are lined up with the petals (antepetalous)

  • Fruits or seeds

    Berry color
    black
    Fruit type (general)
    the fruit is fleshy
    Fruit type (specific)
    • the fruit is a berry (fleshy, with the wall enclosing one or more sections, with two or more seeds)
    • the fruit is a drupe (fleshy, with a firm inner ovary wall that encloses a single seed)
    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 shrub (i.e., a woody plant with several stems growing from the base)

  • Leaves

    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
    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
    40–100 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 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 pinnate (the secondary veins branch off at intervals from the main central vein) and arcuate (slightly arched in the direction of the tip)
    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 crenate (with rounded teeth) or crenulate (with tiny, rounded 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 (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
    wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • fens
    • 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 thin and smooth
    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
    Twig papillae (Vaccinium species only)
    NA
    Twig winter color
    • brown
    • 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

Occurs only in wetlands. (Wetland indicator code: OBL)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
absent
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Connecticut
uncommon to fairly widespread (S-rank: S3S4)
Maine
unranked (S-rank: SNR)
Massachusetts
fairly widespread (S-rank: S4)
New Hampshire
uncommon (S-rank: S3), W (code: W)

From Flora Novae Angliae dichotomous key

1.  Rhamnus alnifolia ĽHér. N

alder-leaved buckthorn. CT, MA, ME, NH, VT. Swamps, fens, often associated with Thuja.

Native to North America?

Yes

Sometimes confused with

Rhamnus cathartica:
flowers with 4 sepals, petals, and stamens, leaves alternate, subopposite, or opposite, and plants often armed with a spine-like process near the apex of some branchlets or in the forks of some branches (vs. R. alnifolia, with flowers with 5 sepals, 0 petals, and 5 stamens, leaves alternate, and branches unarmed).

Family

Rhamnaceae

Genus

Rhamnus