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Erigeron canadensis — Canada fleabane

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Facts

Canada fleabane, also called Horseweed, is native to North America and has become a weed in South America, Europe, Asia, and Africa.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

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
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf type
leaves are simple (lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
  • the edge of the leaf blade has no teeth or lobes
  • the edge of the leaf blade has teeth
Flower type in flower heads
the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
Ray flower color
  • blue to purple
  • pink to red
  • white
Tuft or plume on fruit
at least a part of the plume is made up of fine bristles
Spines on plant
the plant has no spines
Leaf blade length
20–100 mm
Disk flower number
  • 11-20
  • 21-50
  • 6-10
Show all characteristics
  • Flowers

    Bases of bract appendages
    NA
    Bract color
    the bracts are not colored or tinged with with pink, red or purple
    Bract inner side hairs
    the bracts are not hairy on their inner surfaces
    Bract margins
    there are few or no fine hairs along the bract margins
    Bract outer side hair type
    • the bracts are hairy, with simple hairs on their outer surface
    • the bracts are not hairy on their outer surface
    Bract outer side hairs
    • the bracts are hairy on their outer surfaces
    • the bracts are not hairy on their outer surfaces
    Bract separation
    the bracts appear completely unconnected to one another on all flower heads
    Bract shape
    • the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
    • the main bracts are linear (long and very narrow)
    Bract spines
    the bracts have no spines
    Bract texture
    the bracts have a similar texture to a leaf
    Bract tip color
    • the tips are a different color from the center of the bract
    • the tips are the same color as the center of the bract
    Bract tip extension appearance
    NA
    Bract tip extension edge
    there are no projections from the bract tips
    Bract tip orientation
    the bracts are pressed against the plant, or spreading out at the tips
    Bract tip shape
    the tips of the bracts are acuminate (tapered to a narrow point)
    Bracts
    the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
    Disk flower color
    yellow
    Disk flower lobe number
    5
    Disk flower number
    • 11-20
    • 21-50
    • 6-10
    Disk flower reproductive parts
    the disk flower has both pollen- and seed-producing parts
    Disk width
    1–2 mm
    Flower head number
    each flowering stem has four or more flower heads on it
    Flower head outer flowers
    at the outer edge of the flower head, each flower has a single enlarged lobe or strap
    Flower head platform
    the base has no bristles or papery scales
    Flower head platform surface
    NA
    Flower head position
    each of the flower heads is separate on its own peduncle (stalk), not clustered in groups
    Flower head profile
    the disk is flat or nearly flat across the top
    Flower head shape
    the flower head is shaped like a cone with the point up
    Flower type in flower heads
    the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
    Height of flower head base
    3–4 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    • the inflorescence is flat-topped in profile
    • the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
    Inflorescence stem
    hairs are present on the stem of the inflorescence
    Ovary attachment
    the ovary is attached at or near the base
    Ovary cross-section
    the ovary is compressed (flattened)
    Ovary hair type
    the ovary has hairs on it, but the hairs have no glands
    Ovary hairs
    the ovary has hairs on it
    Ovary lines or ribs
    there are two lines or ribs visible on the ovary
    Ovary profile
    in profile, the ovary is lanceolate (widest below the middle, tapering to both ends)
    Ovary wing number
    • 0
    • NA
    Peduncle hair type
    the hairs on the peduncles are simple (not branched), don’t have glands, and are not woolly
    Peduncle hairs
    the peduncles are hairy
    Peduncle orientation
    the flower heads are held upright, or slightly angled outwards
    Ray flower color
    • blue to purple
    • pink to red
    • white
    Ray flower reproductive parts
    the ray flowers have carpels or stamens, but not both
    Ray flowers
    • 16-25
    • 26-50
    Ray length
    0.5–2 mm
    Reproductive system
    some of the flowers on the plant have only carpels or stamens, while others have both carpels and stamens
    Scale tip
    NA
    Swelling at base of flower head
    the peduncles are not swollen, or only slightly
    Width of flower head base
    2–5 mm
  • Fruits or seeds

    Dispersal unit
    the seeds fall off or are dispersed separately from one another
    Number of pappus parts
    11 or more
    Ovary length in developed fruit
    1–1.5 mm
    Seed hair tuft bases
    the pappus hairs are not attached to one another near the base
    Seed hair tuft color
    • the pappus hairs are tan to dark brown
    • the pappus hairs are white or off-white
    Seed hair tuft details
    the pappus hairs are hooked or barbed
    Seed hair tuft length
    2–3 mm
    Seed hair tuft tips
    the pappus hairs are slender
    Seed hairs uniform
    all the pappus hairs are approximately the same length
    Seed tuft scale number
    0
    Seed tuft type
    the pappus is made of very fine hairs or bristles
    Top of disk flower ovary
    NA
    Tuft or plume on fruit
    at least a part of the plume is made up of fine bristles
  • Glands or sap

    Bract resin
    the bracts have no resin or resin glands
    Leaf blade glands
    the leaf blades have no glandular (translucent) dots or scales
    Ovary glands
    there are no visible glands on the ovary
    Sap
    the sap is clear and watery
  • Growth form

    Growth form
    the plant has one or more free-standing stems
    Horizontal rooting stem
    there are no stolons
    Plant lifespan
    the plant is annual, it lacks evidence of previous years' growth
    Spines on plant
    the plant has no spines
    Underground organs
    there is a thickened taproot on the plant
  • Leaves

    Final leaf segment length (compound lvs only)
    0 mm
    Final leaf segment width (compound lvs only)
    0 mm
    Hairs on underside of leaf blade
    the underside of the leaf is not hairy, or has very few hairs
    Hairs on upper side of leaf blade
    the upper side of the leaf is not hairy, or has very few hairs
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    the leaf has no petiole
    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
    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
    • the edge of the leaf blade has teeth
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    20–100 mm
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    Leaf blade surface colors
    there is no noticeable color variation on the upper surface of the leaf
    Leaf blade tip
    the tip of the leaf blade is acute (sharply pointed)
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    Leaf blade width
    4–15 mm
    Leaf disposition
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have no leaf stalks, but attach directly to the stem
    Leaf stalk length
    0 mm
    Leaf tip extension
    NA
    Leaf tufts in axils
    there are no clusters of smaller leaves
    Leaf type
    leaves are simple (lobed or unlobed but not separated into leaflets)
    Leaflet number
    0
    Specific leaf type
    the leaves are simple (lobed or unlobed but not separated into leaflets
    Teeth per side of leaf blade
    At least 0
  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Scent

    Plant odor
    the plant does not have much of an odor
  • Stem, shoot, branch

    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem internode hair direction
    the hairs point mostly upwards to outwards
    Stem internode hair type
    the hairs on the stem are plain, without glands or branches, and not tangled
    Stem internode hairs
    the stem has hairs between the nodes
    Stem wings
    the stem does not have wings on it

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

Distribution

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

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
unranked (S-rank: SNR)

var. canadensis

Massachusetts
unranked (S-rank: SNR)

var. pusilla

Massachusetts
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

3.  Erigeron canadensis L. N

Canada fleabane. Conyza canadensis (L.) Cronq.; C. canadensis (L.) Cronq. var. pusilla (Nutt.) Cronq.; C. parva Cronq.; Erigeron canadensis L. var. pusillus (Nutt.) Boivin; E. pusillus Nutt.; Leptilon canadense (L.) Britt.; L. pusillum (Nutt.) Britt. • CT, MA, ME, NH, RI, VT. Fields, roadsides, railroads, disturbed soil.

Native to North America?

Yes

Synonyms

  • Conyza canadensis (L.) Cronq.
  • Conyza canadensis (L.) Cronq. var. pusilla (Nutt.) Cronq.
  • Conyza parva Cronq.
  • Erigeron canadensis var. pusillus (Nutt.) Boivin
  • Erigeron pusillus Nutt.
  • Leptilon canadense (L.) Britt.
  • Leptilon pusillum (Nutt.) Britt.

Family

Asteraceae

Genus

Erigeron