Alnus viridis — green alder

Characteristics

• Buds or leaf scars

  Bud position relative to scar

  the winter bud has a leaf scar just below it

  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

  Bundle scar number

  3

  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 distribution

  the winter buds are distributed fairly evenly along the twig

  Winter bud scale hairs

  the winter bud scales have no hairs on them

  Winter bud scales

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

  Winter bud shape

  • the winter buds are ellipsoid (elliptical in three dimensions)
  • the winter buds are ovoid (egg-shaped)

  Winter bud stalks

  • the winter buds have no stalks
  • the winter buds have short 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 two cycles of petal- or sepal-like structures

  Petal appearance

  NA

  Petal fusion

  NA

  Sepal appearance

  the sepals resemble leaves in color and texture

  Sepal cilia (Ilex)

  NA

  Sepals fused only to sepals

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

  Stamen number

  4

  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 cordate (heart-shaped, with rounded lobes)
  • 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

  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

  Leaf blade length

  30–85 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 orbicular (roughly circular, as wide as long)
  • 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)

  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

  30–60 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 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 has teeth, which themselves have smaller teeth on them
  • 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
  • wetlands

  New England state

  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont

  Specific habitat

  • alpine or subalpine zones
  • edges of forests
  • edges of wetlands
  • meadows or fields
  • shores of rivers or lakes
  • swamps
  • talus or rocky slopes

• Scent

  Plant odor

  • the plant does not have much of an odor, or it has an unpleasant or repellant odor
  • the plant has a pleasantly aromatic 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

  Pith shape

  the outline of the pith in a twig is roughly triangular

  Pith type

  the pith inside the twig is solid, completely filled with spongy tissue

  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

  Twig papillae (Vaccinium species only)

  NA

  Twig scales

  there are no scales on the twig surface

  Twig winter color

  • brown
  • gray
  • 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)

In New England

From Flora Novae Angliae dichotomous key