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Native Plant Trust: Go Botany Discover thousands of New England plants

Betula minor — dwarf birch

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Facts

Dwarf birch is a shrub up to 9 feet (3 m) tall, which inhabits ravines and plateaus of the alpine regions of Vermont, Maine, and New Hampshire. It is listed as rare in the latter two states. Its dark brown branches are hairless or with a few soft hairs, but some plants are intermediate in character between B. glandulosa and B. cordifolia, two species with which it overlaps in range and habitats. This shrub blooms in June-July in Maine.

Habitat

Alpine or subalpine zones, mountain summits and plateaus

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Maine
  • New Hampshire
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
15–60 mm
Leaf blade width
15–50 mm
Leaf stalk
the leaves have leaf stalks
Fruit type (general)
the fruit is dry but does not split open when ripe
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
    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
    there is no terminal bud on the branch
    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
    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 does not have a hypanthium
    Inflorescence position
    the inflorescences grow on the twigs
    Inflorescence type
    the inflorescence is an ament (catkin; slender, usually pendulous inflorescence with crowded unisexual flowers)
    Number of pistils
    1
    Ovary position
    the ovary is below the point of petal and/or sepal attachment
    Petal and sepal arrangement
    • the flower includes only one cycle of petals or sepals
    • the flower lacks sepals and petals
    Petal appearance
    NA
    Petal fusion
    NA
    Sepal cilia (Ilex)
    NA
    Sepal tip glands
    there are no glands at the tips of the sepal lobes
    Sepals fused only to sepals
    • NA
    • the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen number
    1 or 2
    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 but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
    Nut with spines (Fagaceae)
    NA
    Wings on fruit
    the fruit has one or more wings on it

  • 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 cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    • the base of the leaf blade is rounded
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    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 teeth
    Leaf blade edges (Acer)
    NA
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    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
    15–60 mm
    Leaf blade scales
    there are no scales on the leaf blades
    Leaf blade shape
    the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    Leaf blade texture
    • the leaf blade is coriaceous (has a firm, leathery 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 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
    15–50 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 leaf blade margin is serrate (with forward-pointing) or dentate (with outward-pointing) with medium-sized to coarse teeth
    • the leaf blade margin is serrulate (with forward-pointing) or denticulate (with outward-pointing) with tiny 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
    terrestrial
    New England state
    • Maine
    • New Hampshire
    Specific habitat
    • alpine or subalpine zones
    • mountain summits and plateaus

  • 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 clearly lenticels on the twigs
    Short shoots
    there are peg- or knob-like shoots present
    Twig bloom
    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

Not classified

In New England

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.

Maine
extremely rare (S-rank: S1), endangered (code: E)
New Hampshire
rare (S-rank: S2), threatened (code: T)
Vermont
extremely rare (S-rank: S1), endangered (code: E)

From Flora Novae Angliae dichotomous key

5.  Betula minor (Tuckerman) Fern. NC

dwarf birch. Betula papyracea Ait. var. minor Tuckerman; B. pubescens Ehrh. ssp. minor (Tuckerman) A. & D. Löve; B. saxophila Lepage • ME, NH, vt. Alpine plateaus, slopes, gullies, and ravines. This species is sometimes often considered to be a hybrid-derived species 
of Betula cordifolia and B. glandulosa, given that it is intermediate in morphology and occurs where those species are sympatric. There may be two taxa involved here. One is characterized by glabrous branchlets and leaf blades and samaras 2.5–5 mm wide with individual wings wider than achene body ( B. minor s.s.). The other is characterized by pubescent young branchlets and leaf blades and samaras 2–3.5 mm wide with individual wings up to as wide as the achene body ( B. borealis Spach sensu Fernald 1950b; but this name misapplied as it consists of material of B. pumila). I am tentatively following Furlow (1997) in treating B. minor as a single, variable taxon.

Native to North America?

Yes

Sometimes confused with

Betula pubescens:
bark gray white, lateral lobes of carpellate scales divergent, and plants trees to 20 m tall (vs. B. minor, with bark dark brown, lateral lobes of carpellate scales ascending, and plants shrubs to 3 m tall).
Betula glandulosa:
leaf blades 0.5-3 cm long that are single serrate with teeth that are obtuse to rounded at the apex, and each wing of samara narrower than the body (vs. B. minor, with leaf blades mostly 1.5-5.5 cm long, obscurely double serrate with teeth that are obtuse to acute at the apex, and each wing of samara as wide as or wider than the body).

Synonyms

  • Betula papyracea Ait. var. minor Tuckerman
  • Betula pubescens Ehrh. ssp. minor (Tuckerman) A. & D. Löve
  • Betula saxophila Lepage

Family

Betulaceae

Genus

Betula