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- Eupatorium pilosum
Eupatorium pilosum — ragged thoroughwort
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Facts
Ragged thoroughwort is found in damp to seasonally wet sandy soils in southern New England. It is distinguished from the similar round-leaved thoroughwort (Eupatorium rotundifolium) on the basis of differences in the leaves.
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.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- Rhode Island
- 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
- opposite: there are two 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
- 30–90 mm
- Disk flower number
-
- 11-20
- 6-10
-
Flowers
- Bract color
- the bracts are not colored or tinged with pink, red or purple
- Bract cycle number
-
- there are three or more cycles of bracts
- there are two main cycles of bracts
- Bract keels
- the bracts do not have keels
- Bract outer side hair type
- the bracts are hairy, with simple hairs on their outer surface
- Bract outer side hairs
- the bracts are hairy on their outer surfaces
- Bract shape
-
- the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
- the main bracts are oblong (roughly rectangular but rounded at the ends)
- 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
- Bract tip orientation
- the bracts are pressed against the plant, or spreading out at the tips
- Bract tip shape
-
- the tips of the bracts acute (have a sharp point)
- the tips of the bracts are acuminate (tapered to a narrow point)
- Bract width
- 1–1.5
- Bracts
- there are at least two distinct forms of bracts in different cycles
- Disk flower color
- white
- Disk flower lobe number
- 5
- Disk flower number
-
- 11-20
- 6-10
- Disk flower proportions
- NA
- Disk flower reproductive parts
- the disk flower has both pollen- and seed-producing parts
- Disk flower shape
- the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel
- 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, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk
- Flower head platform
- the base has no bristles or papery scales
- Flower head platform surface
- NA
- Flower head position
- some or all the flower heads are grouped in clusters of two or more
- Flower head profile
-
- the disk is flat or nearly flat across the top
- the disk is rounded across the top
- Flower head shape
- the sides of the flower head diverge like a funnel
- Flower type in flower heads
- the flower head has disk flowers only, and lacks the strap-shaped flowers
- Height of flower head base
- 4–7 mm
- Inflorescence branching (Solidago)
- NA
- Inflorescence shape
- the inflorescence is flat-topped in profile
- Inflorescence stem
- hairs are present on the stem of the inflorescence
- Ovary cross-section
- the ovary has five or more corners in cross-section
- Ovary hair type
- the ovary has no hairs on it
- Ovary hairs
- the ovary has no hairs on it
- Ovary lines or ribs
- there are four to six lines or ribs visible on the ovary
- 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
- NA
- Ray flower reproductive parts
- NA
- Ray flowers
- NA
- Ray length
- 0 mm
- Reproductive system
- all the flowers on the plant contain both carpels and stamens
- Scale tip
- NA
- Smaller bracts at base of bracts
- there is a cycle of much smaller bracts outside the cycle of larger and longer bracts
- Style branch number
- the style has two branches
- Width of flower head base
- 1–6 mm
-
Fruits or seeds
- Number of pappus parts
- 11 or more
- Ovary length in developed fruit
- 3–4 mm
- Seed hair tuft details
- the pappus hairs are hooked or barbed
- Seed hair tuft length
- 4–5 mm
- Seed hair tuft tips
- at least some of the pappus hairs are broader at their tips than their bases
- 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 resin or resin glands
- Leaf blade glands
- the leaf blades have glandular (translucent) dots or scales
- Ovary glands
- there are glands on the ovary surface
- 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 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
- Leaf arrangement
-
- alternate: there is one leaf per node along the stem
- opposite: there are two leaves 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
- the base of the leaf blade is rounded
- 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 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
- 30–90 mm
- Leaf blade shape
-
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is oblong (rectangular but with rounded ends)
- the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- 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)
- the tip of the leaf blade is rounded, with no point
- Leaf blade veins
- the leaf blade has three main veins running from the base towards the tip
- Leaf blade width
- 10–40 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
- At least 0 mm
- 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
- 3–12
-
Place
- Habitat
- wetlands
- New England state
-
- Connecticut
- Massachusetts
- 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
- 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 wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- present
- Vermont
- absent
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
6. Eupatorium pilosum Walt. N
ragged thoroughwort. Eupatorium rotundifolium L. var. saundersii (Porter ex Britt.) Cronq. • CT, MA, RI. Mesic to wet-mesic or seasonally hydric, sandy soils of pond shores, fields, and depressions.
Native to North America?
Yes
Sometimes confused with
- Eupatorium album:
- involucre 8–11 mm tall, with abaxially glabrous or sparsely pubescent involucral bracts (vs. E. pilosum, with the involucre 4–7 mm tall, with abaxially moderately to densely pubescent involucral bracts).
- Eupatorium pubescens:
- leaf blades oblong-ovate to suborbicular, each margin with 8–25 teeth (vs. E. pilosum, with leaf blades oblong or oblong-lanceolate to narrow-ovate, each margin with 3–12 coarse teeth, sometimes the blades more incised with lobe-like teeth near the base).
Synonyms
- Eupatorium rotundifolium L. var. saundersii (Porter ex Britt.) Cronq.