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- Asteraceae Group 4
- Erigeron
- Erigeron canadensis
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
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf type
- leaves are simple (i.e., 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
-
Flowers
- Bases of bract appendages
- NA
- Bract color
- the bracts are not colored or tinged 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 (i.e., lobed or unlobed but not separated into leaflets)
- Leaflet number
- 0
- Specific leaf type
- the leaves are simple (i.e., 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
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- widespread (S-rank: S5)
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.