Eutrochium dubium (Willd. ex Poir.) E.E. Lamont

coastal plain Joe-Pye weed

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Coastal plain Joe-Pye weed is restricted to the coastal plain and areas along major river systems, from South Carolina to Maine. It is difficult to distinguish from related species, particularly spotted Joe-Pye weed (Eutrochium maculatum). The main difference is Coastal plain Joe-Pye weed has fewer flowers per capitulum (flower head), roughly 5-9 versus 9-22 in spotted Joe-Pye weed.

Habitat

Meadows and fields, shores of rivers or lakes

Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
Leaf type
leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
whorled: there are three or more leaves per node along the stem
Leaf blade edges
the edge of the leaf blade has teeth
Flower type in flower heads
the flower head has disk flowers only, and lacks the strap-shaped flowers
Ray flower color
NA
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
50–160 mm
Disk flower number
  • 1-5
  • 6-10
Show All Characteristics
  • Flowers
    Bases of bract appendages
    NA
    Bract cycle number
    there are three or more cycles of bracts
    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 tip color
    the tips are the same color as the center of the bract
    Bract tip shape
    the tips of the bracts are obtuse (have a blunt point)
    Disk flower color
    blue to purple
    Disk flower lobe number
    5
    Disk flower number
    • 1-5
    • 6-10
    Disk flower reproductive parts
    the disk flower has both pollen- and seed-producing parts
    Flower head platform
    the base has no bristles or papery scales
    Flower head platform surface
    NA
    Flower head shape
    the sides of the flower head are roughly parallel, like a cylinder
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    6.5–9 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
    Ovary attachment
    the ovary is attached at or near the base
    Ovary lines or ribs
    there are four to six lines or ribs visible on the ovary
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Ray length
    0 mm
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    Scale tip
    NA
    Width of flower head base
    2.5–5 mm
  • Fruits or seeds
    Number of pappus parts
    11 or more
    Ovary length in developed fruit
    3–4.5 mm
    Seed hair tuft color
    • the pappus hairs are pale red to red-brown or purple
    • the pappus hairs are white or off-white
    Seed hair tuft details
    the pappus hairs are hooked or barbed
    Seed hair tuft length
    5–7 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
    Leaf blade glands
    the leaf blades have glandular (translucent) dots or scales
    Sap
    the sap is clear and watery
  • Growth form
    Growth form
    the plant has one or more free-standing stems
    Plant lifespan
    the plant is perennial, it shows evidence of previous year's leaves, stems or stem bases
    Spines on plant
    the plant has no spines
    Underground organs
    • the plant has a caudex (the root mass is firm and hardened at the top)
    • the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • 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 fuzzy or hairy
    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 arrangement
    whorled: there are three or more leaves per node along the stem
    Leaf blade base
    the leaf has a distinct petiole
    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 hairs
    the leaf blade has hairs with glands at their tips
    Leaf blade length
    50–160 mm
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    • the leaf blade is triangular, with the stalk or attachment point on one of the sides
    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 acuminate (tapers to a long, thin point)
    • the tip of the leaf blade is acute (sharply pointed)
    Leaf blade veins
    the leaf blade has three main veins running from the base towards the tip
    Leaf blade width
    20–80 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 leaf stalks
    Leaf stalk length
    7–25 mm
    Leaf tip extension
    NA
    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
  • Place
    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    Specific habitat
    • meadows or fields
    • shores of rivers or lakes
  • 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
    • the stem has a powdery or waxy film on it that can be rubbed away
    • there is no powdery or waxy film on the stem
    Stem internode hair length
    At least 0 mm
    Stem internode hair type
    • at least some of the hairs on the stem have glands
    • the stem has no hairs between the nodes
    Stem internode hairs
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes
    Stem wings
    the stem does not have wings on it

Wetland Status

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

New England Distribution and Conservation Status

Distribution

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

Conservation Status

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

Maine
uncommon (uncertain) (S-rank: S3?)
Massachusetts
widespread (S-rank: S5)

Native to North America?

Yes

Sometimes Confused With

Eutrochium maculatum:
flower heads with mostly 9-22 flowers, arranged in a relatively flat-topped array and leaf blades not both abruptly tapered to a leaf stalk and conspicuously 3-veined at the base (vs. E. dubium, with flower heads with mostly 5-9 flowers, arranged in a round-topped array and leaf blades both abruptly tapered to a leaf stalk and conspicuously 3-veined at base).

Synonyms

  • Eupatoriadelphus dubius (Willd. ex Poir.) King & H.E. Robins.
  • Eupatorium dubium Willd. ex Poir.
  • Eupatorium ternifolium Ell.

Family

Asteraceae

Genus

Eutrochium

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Information from Dichotomous Key of Flora Novae Angliae

1.  Eutrochium dubium (Willd. ex Poir.) E.E. Lamont N

coastal plain Joe-Pye weed. Eupatoriadelphus dubius (Willd. ex Poir.) King & H.E. Robins.; Eupatorium dubium Willd. ex Poir.; E. ternifolium Ell. • CT, MA, ME, NH, RI; restricted in ME to southern portion of state. Pond and stream shores, edges of pools, low meadows, wet fields. Reports of this species in VT are based primarily on collections of Eutrochium maculatum.