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- Eutrochium dubium
Eutrochium dubium — coastal plain Joe-Pye weed
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Facts
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
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.
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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
-
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)
In New England
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)
From Flora Novae Angliae dichotomous key
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.
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.