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• Empetrum atropurpureum

Empetrum atropurpureum — purple crowberry

Facts

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

• 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

From the dichotomous key of Flora Novae Angliae