Arctium tomentosum P. Mill.

woolly burdock

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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

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

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
Show All Characteristics
  • 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

New England Distribution and Conservation Status

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
unranked (S-rank: SNR)

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).

Family

Asteraceae

Genus

Arctium

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Information from Dichotomous Key of Flora Novae Angliae

3.  Arctium tomentosum P. Mill. E

woolly burdock. CT, MA, ME, NH, VT. Fields, roadsides, vacant lots.