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- Asteraceae Group 3
- Arctium
- Arctium tomentosum
Arctium tomentosum — woolly burdock
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Facts
Woolly burdock is a Eurasian introduction that can be distinguished from the other burdocks (Arctium) by the abundant cobwebby hairs that cover the floral bracts below their hooked tips. Woolly burdock roots are used in European traditional medicine.
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
- 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
- basal: the leaves are growing only at the base of the plant
- 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 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
- 300–400 mm
- Flower head width
- 20–27 mm
- Disk flower number
- 21-50
-
Flowers
- Bases of bract appendages
- NA
- Bract color
-
- the bracts are colored, or at least tinged with, pink, red or purple
- the bracts are not colored or tinged with pink, red or purple
- Bract cycle number
- there are three or more cycles of bracts
- Bract margins
- there are fine hairs along the bract margins
- Bract outer side hair type
-
- the bracts are hairy on their outer surfaces, with curled, tangled, matted, or woolly hairs
- the bracts are hairy on their outer surfaces, with hairs having glands (a swelling at the tip of the hair)
- 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 linear (long and very narrow)
- the main bracts are of a different shape than the given options
- Bract tip orientation
-
- the bracts are pressed against the plant, or spreading out at the tips
- the tips of the bracts curve outwards and downwards from the plant
- Bract tip shape
-
- NA
- the bract tips are blunt or rounded, with a notch at the center
- the tips of the bracts are acuminate (tapered to a narrow point)
- Bract width
- 1–2
- Disk flower color
-
- blue to purple
- pink to red
- Disk flower number
- 21-50
- 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
- each flowering stem has only one to three 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 fine, short hairs on it
- 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
- Flower head shape
- NA
- Flower head width
- 20–27 mm
- Flower type in flower heads
- the flower head has disk flowers only, and lacks the strap-shaped flowers
- Height of flower head base
- 12–20 mm
- Inflorescence branching (Solidago)
- NA
- Inflorescence shape
- the inflorescence is flat-topped in profile
- 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 no hairs on it
- Ovary hairs
- the ovary has no hairs on it
- Ovary profile
-
- in profile, the ovary is roughly egg-shaped, but widest above the middle
- in profile, the ovary is roughly elliptical (widest in the middle, tapering to both ends)
- Ovary surface
- the ovary surface is textured with tiny points, bumps or wrinkles
- Peduncle hair type
-
- NA
- the hairs on the peduncles appear tangled or woolly
- Peduncle hairs
- the peduncles are hairy
- Peduncle length
- 15–120 mm
- 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
- Style branch number
- the style has two branches
- Style branches
- the style branch is narrow at the tip, or the style branches are narrow at the tips
- Width of flower head base
- 15–25 mm
-
Fruits or seeds
- Dispersal unit
- the entire flower head falls off or disperses as a unit
- Ovary length in developed fruit
- 5–8 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
- Seed hair tuft length
- 1–3 mm
- 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
- 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 biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit
- 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 fuzzy or hairy
- 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
- basal: the leaves are growing only at the base of the plant
- Leaf blade base
- the leaf has a distinct petiole
- Leaf blade base shape
- the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
- 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 hairs
- the leaf blade has tangled or woolly-looking hairs
- Leaf blade length
- 300–400 mm
- Leaf blade shape
- 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 obtuse (bluntly pointed)
- Leaf blade veins
- the leaf blade has one main vein running from the base towards the tip
- Leaf blade width
- 160–280 mm
- Leaf disposition
- the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
- Leaf spines
- there are no spines on the leaf edges
- Leaf stalk
-
- the leaves have leaf stalks
- the leaves have no leaf stalks, but attach directly to the stem
- Leaf stalk length
- 100–150 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
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- 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
- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
- Stem internode hair direction
- the hairs point mostly upwards to outwards
- Stem internode hair type
- at least some of the hairs on the stem have glands
- Stem internode hairs
- the stem has hairs between the nodes
Wetland status
Not classified
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
3. Arctium tomentosum P. Mill. E
woolly burdock. CT, MA, ME, NH, VT. Fields, roadsides, vacant lots.
Native to North America?
No
Sometimes confused with
- Arctium lappa:
- involucres 25-45 mm wide, the bracts glabrous or thinly pubescent, and corollas glabrous (vs. A. tomentosum, with involucres 15-25 mm wide, the bracts tomentose, and corollas glandular pubescent).