Empetrum atropurpureum Fern. & Wieg.

purple crowberry

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Purple crowberry is a creeping shrub with needle-like leaves. It is a denizen of boreal habitats, and in New England, it inhabits mountaintops and alpine zones. It's easy to mix this species up with its more common cousin, E. nigrum, but look closely at the twigs. Empetrum atropurpureum has dense white hairs on the twigs, whereas E. nigrum has stipitate-glandular hairs. The mature fruits of purple crowberry are purple (i.e., not red) and those of black crowberry are, logically, black.

Habitat

Alpine or subalpine zones, mountain summits and plateaus, ridges or ledges

Characteristics

Habitat
terrestrial
New England state
  • Maine
  • 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 no teeth or lobes
Leaf duration
the leaves remain green all winter
armature on plant
the plant does not have spines, prickles, or thorns
Leaf blade length
4–7 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
  • purple
  • red
Bud scale number
there are two scales on the winter bud, and their edges meet
Show All Characteristics
  • 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
    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
    Winter bud scale hairs
    the winter bud scales are hairy
  • Flowers
    Anther color
    there is a noticeable pink, reddish or purplish tint to the anthers
    Carpels fused
    the carpels are fused to one another
    Enlarged sterile flowers
    there are no enlarged sterile flowers on the plant
    Flower petal color
    white
    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 hairs
    there are no hairs on the inflorescence
    Inflorescence position
    the inflorescences grow on the twigs
    Inflorescence type
    • the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
    • the inflorescence has only one flower on it
    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 appearance
    the sepals resemble petals in color and texture
    Sepal cilia (Ilex)
    NA
    Sepal tip glands
    there are no glands at the tips of the sepal lobes
    Sepals fused only to sepals
    the sepals are separate from one another
    Stamen number
    4
    Stamen position relative to petals
    the stamens are lined up with the petals (antepetalous)
    Stamens fused
    the stamens are not fused to one another
  • Fruits or seeds
    Berry color
    purple
    Fruit tissue origin
    there are no flower parts that form part of the fruit
    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)
    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 underside of leaf blade
    • the underside of the leaf has hairs on it
    • the underside of the leaf has no hairs
    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 attenuate (tapering very gradually to a prolonged tip)
    • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    Leaf blade base symmetry
    the leaf blade base is symmetrical
    Leaf blade bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    the edge of the leaf blade has no teeth or lobes
    Leaf blade edges (Acer)
    NA
    Leaf blade flatness
    the edges of the leaf are curled under
    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
    4–7 mm
    Leaf blade scales
    there are no scales on the leaf blades
    Leaf blade shape
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblong (rectangular but with rounded ends)
    Leaf blade texture
    the leaf blade is coriaceous (has a firm, leathery 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 duration
    the leaves remain green all winter
    Leaf form
    the plant has leaves that are needle-like (narrow and thickened) or scale-like (small, thin and lacking leaf stalks)
    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 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 edge of the leaf blade is entire (has no teeth or lobes)
    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
    there are no stipules on the plant, or they fall off as the leaf expands
  • Place
    Habitat
    terrestrial
    New England state
    • Maine
    • New Hampshire
    • Vermont
    Specific habitat
    • alpine or subalpine zones
    • mountain summits and plateaus
    • ridges or ledges
  • 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
    Lenticels on twigs
    there are no lenticels on the twigs, or they are very hard to see
    Short shoots
    there are peg- or knob-like shoots present
    Twig bloom
    there is no bloom on the twig
    Twig hairs
    the twigs have hairs, but the hairs do not have glands
    Twig papillae (Vaccinium species only)
    NA
    Twig scales
    there are no scales on the twig surface
    Twig winter color
    • brown
    • 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

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

New England Distribution and Conservation Status

Distribution

Connecticut
absent
Maine
present
Massachusetts
absent
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.

New Hampshire
uncommon (S-rank: S3), W (code: W)
Vermont
extirpated (S-rank: SX)

Native to North America?

Yes

Sometimes Confused With

Empetrum nigrum:
fruit black and branchlets without white hairs (vs. E. atropurpureum, with fruit purple and branchlets covered with short, white hairs).
Corema conradii:
flowers and fruits in small, terminal clusters, leaf blades minutely denticulate, and plants ascending to erect (vs. E. atropurpureum, with flowers and fruits on pedicels from the axils of leaves, leaf blades entire, and plants trailing over the ground).

Synonyms

  • Empetrum eamesii Fern. & Wieg. ssp. atropurpureum (Fern. & Wieg.) D. Löve
  • Empetrum nigrum L. var. atropurpureum (Fern. & Wieg.) Boivin
  • Empetrum nigrum L. var. purpureum (Raf.) A. DC.
  • Empetrum Vahl ex Willd. var. atropurpureum (Fern. & Wieg.) R. Good

Family

Ericaceae

Genus

Empetrum

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Information from Dichotomous Key of Flora Novae Angliae

1.  Empetrum atropurpureum Fern. & Wieg. N

red crowberry. Empetrum eamesii Fern. & Wieg. ssp. atropurpureum (Fern. & Wieg.) D. Löve; 
 E. nigrum L. var. atropurpureum (Fern. & Wieg.) Boivin; E. nigrum L. var. purpureum (Raf.) A. 
DC.; E. rubrum Vahl ex Willd. var. atropurpureum (Fern. & Wieg.) R. Good • ME, NH, VT. Open ledges and plateaus, usually at high elevation in subalpine and alpine situations. This species is frequently confused with Empetrum nigrum, especially when collections are vegetative.