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• Dichotomous Key
• Asteraceae
• Asteraceae Group 3
• Arctium
• Arctium minus

Arctium minus — common burdock

Facts

Native to Europe and Asia, common burdock is introduced across most of North America. The roots and young leaves and leaf stalks are edible. The roots are widely used in herbal medicine and are considered by some to be effective against skin conditions, infections, and in removing heavy metals from the body.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

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 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, 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 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)

  Bract spines

  there is just one simple spine at the tip of the bract

  Disk flower color

  • blue to purple
  • pink to red
  • white

  Disk flower lobe number

  5

  Disk flower number

  21-50

  Disk flower reproductive parts

  the disk flower has both pollen- and seed-producing parts

  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 platform surface

  NA

  Flower head profile

  the disk is flat or nearly flat across the top

  Flower head shape

  the flower head is hemispherical (like the bottom half of a sphere)

  Flower head width

  15–25 mm

  Flower type in flower heads

  the flower head has disk flowers only, and lacks the strap-shaped flowers

  Height of flower head base

  10–17 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  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 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 surface

  the ovary surface is textured with tiny points, bumps or wrinkles

  Peduncle length

  0–90 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

  Scale tip

  NA

  Smaller bracts at base of bracts

  there is no smaller, outer cycle of bracts

  Width of flower head base

  15–40 mm

• Fruits or seeds

  Dispersal unit

  the entire flower head falls off or disperses as a unit

  Ovary length in developed fruit

  4–8 mm

  Seed hair tuft color

  the pappus hairs are white or off-white

  Seed hair tuft details

  the pappus hairs are hooked or barbed

  Seed hair tuft length

  1–3.5 mm

  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 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 fuzzy or hairy

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  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 lobes, or it has both teeth and lobes
  • 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

  300–600 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)

  Leaf blade veins

  the leaf blade has one main vein running from the base towards the tip

  Leaf blade width

  150–350 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

  150–500 mm

  Leaf tip extension

  NA

  Leaf type

  leaves are simple (lobed or unlobed but not separated into leaflets)

  Leaflet number

  0

  Specific leaf type

  the leaves are simple (lobed or unlobed but not separated into leaflets

  Teeth per side of leaf blade

  At least 0

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • 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

  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 hairs

  the stem has hairs between the nodes

  Stem wings

  the stem does not have wings on it

Wetland status

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

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae