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• Rhododendron
• Rhododendron canadense

Rhododendron canadense — Canada rosebay, rhodora

Facts

Rhodora is a small shrub that brightens up bogs and wet woods with its gorgeous pink flowers, which emerge slightly earlier than the gray-green leaves. It is a host plant for the Columbia silkmoth (Hyalophora columbia) in Maine and the northwest. The flowers also attract bees.

Habitat

Anthropogenic (man-made or disturbed habitats), bogs, fens (calcium-rich wetlands), meadows and fields, shores of rivers or lakes

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

  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

  Terminal bud

  the branch has a terminal bud on it

  Winter bud scale hairs

  the winter bud scales are hairy

  Winter bud scales

  the winter bud is perulate (partially or completely covered with one or more scales)

  Winter bud stalks

  the winter buds have no stalks

• Flowers

  Carpels fused

  the carpels are fused to one another

  Enlarged sterile flowers

  there are no enlarged sterile flowers on the plant

  Flower appearance

  • the flowers appear at the same time as the leaves
  • the flowers appear before the leaves

  Flower petal color

  • pink
  • red
  • white

  Flower symmetry

  there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)

  Hairs on ovary (Amelanchier)

  NA

  Hypanthium present

  the flower does not have a hypanthium

  Inflorescence position

  the inflorescences grow on the twigs

  Inflorescence type

  • the inflorescence is a corymb (with long lower branches and shorter upper branches, giving it a more or less flat-topped look)
  • the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
  • 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 fused to form a tube, cup, or bell shape

  Sepal appearance

  the sepals resemble leaves in color and texture

  Sepal cilia (Ilex)

  NA

  Sepal tip glands

  • there are glands at the tips of the sepal lobes
  • there are no glands at the tips of the sepal lobes

  Sepals fused only to sepals

  the sepals are fused to each other (not other flower parts), at least near their bases

  Stamen number

  10

  Stamen position relative to petals

  NA

  Stamens fused

  the stamens are not fused to one another

• 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 and splits open when ripe

  Fruit type (specific)

  the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release 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 (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

  Hairs on upper side of leaf blade

  the upper side of the leaf is fuzzy or hairy

  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

  there is a noticeable powdery or waxy bloom on the underside of the leaf

  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

  the hairs on the leaf blade are different from the choices given

  Leaf blade length

  10–83 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 oblong (rectangular but with rounded ends)

  Leaf blade texture

  • the leaf blade is herbaceous (has a leafy texture)
  • the leaf blade is membranaceous (thin, flexible, almost translucent)

  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 blade width

  4–30 mm

  Leaf duration

  the leaves drop off in winter (or they wither but persist on the plant)

  Leaf form

  the plant is broad-leaved (with broadly flattened leaf blades)

  Leaf lobe tips (Quercus)

  NA

  Leaf midrib glands

  • the midrib of the leaf blade has glands on the upper surface
  • 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 (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 (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

  wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • bogs
  • fens (calcium-rich wetlands)
  • man-made or disturbed habitats
  • meadows or fields
  • shores of rivers or lakes

• 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
  • the bark of an adult plant peels off easily or hangs off

  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 clearly lenticels on the twigs
  • there are no lenticels on the twigs, or they are very hard to see

  Pith shape

  the outline of the pith in a twig is roughly round

  Short shoots

  there are no peg- or knob-like shoots present

  Twig bloom

  • the twig has bloom on it
  • there is no bloom on the twig

  Twig hairs

  • the twigs have few or no hairs on them
  • the twigs have hairs with glands at their tips
  • 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
  • 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 wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae