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• Rhamnus alnifolia

Rhamnus alnifolia — alder-leaved buckthorn

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

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)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae