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Cirsium discolor — field thistle

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Facts

Field thistle is a native thistle of disturbed areas, usually with damp to wet soils. The young leaves and stems are edible after boiling. Native Americans used the roots to make poultices for treating wounds and boils.

Habitat

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

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • 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 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
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
there are spines on the plant
Leaf blade length
100–500 mm
Disk flower number
  • 21-50
  • more than 50
Show all characteristics
  • 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
    Bract outer side hair type
    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 ovate (egg-shaped)
    Bract spines
    there is just one simple spine at the tip of the bract
    Bract tip color
    the tips are a different color from the center of the bract
    Bract tip extension appearance
    • NA
    • the projections from the bract tips are simple, but may be a different color than the bract
    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
    Bracts
    there are at least two distinct forms of bracts in different cycles
    Disk flower color
    • blue to purple
    • pink to red
    • white
    Disk flower number
    • 21-50
    • more than 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 platform surface
    NA
    Flower head position
    each of the flower heads is separate on its own peduncle (stalk), not clustered in groups
    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 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
    20–40 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    • the flower heads grow in clusters from the axils of the branches or leaves
    • 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 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 lines or ribs
    there are no lines or ribs visible on the ovary
    Ovary profile
    in profile, the ovary is roughly egg-shaped
    Ovary surface
    the ovary surface has no points, bumps or wrinkles, though it may have lines, ribs or wings
    Peduncle length
    0–50 mm
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    Rim at top of ovary
    the central flowers have a disk-shaped platform above the ovary
    Scale tip
    NA
    Style branch number
    the style has two branches
    Width of flower head base
    15–30 mm
  • Fruits or seeds

    Ovary length in developed fruit
    4–5 mm
    Seed hair tuft color
    the pappus hairs are white or off-white
    Seed hair tuft details
    the pappus hairs have smaller hairs along their sides
    Seed hair tuft length
    18–25 mm
    Seed hairs uniform
    all the pappus hairs are approximately the same length
    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 no resin or resin glands
    Leaf blade glands
    the leaf blades have no 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
    • the plant is perennial, it shows evidence of previous year's leaves, stems or stem bases
    Spines on plant
    there are spines on the plant
    Underground organs
    • there are only slender roots on the plant
    • there is a thickened taproot on the plant
  • Leaves

    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
    • basal: the leaves are growing only at the base of the plant
    Leaf blade base
    • the leaf has a distinct petiole
    • the leaf has no petiole
    • the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf
    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
    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 flatness
    the edges of the leaf are curled under
    Leaf blade hairs
    the leaf blade has tangled or woolly-looking hairs
    Leaf blade length
    100–500 mm
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    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 one main vein running from the base towards the tip
    Leaf blade width
    10–250 mm
    Leaf disposition
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaf spines
    there are spines along the leaf edges
    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 leaf has a row of two or more lobes on each side of the central axis
  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Stem, shoot, branch

    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Stem internode hair direction
    • NA
    • 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
    • the stem has no hairs between the nodes
    Stem internode hairs
    the stem has hairs between the nodes
    Stem wings
    the stem does not have wings on it

Wetland status

Occurs only in non-wetlands. (Wetland indicator code: UPL)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
widespread (S-rank: S5)
Vermont
rare (S-rank: S2)

From Flora Novae Angliae dichotomous key

3.  Cirsium discolor (Muhl. ex Willd.) Spreng. N

field thistle. Carduus discolor (Muhl. ex Willd.) Nutt. • CT, MA, ME, NH, RI, VT. Fields, roadsides, disturbed soil, often on mesic to wet-mesic soil.

Native to North America?

Yes

Sometimes confused with

Cirsium flodmanii:
leaf blades usually thinly tomentose on the adaxial surface, stem uniforny and persistently tomentose, and pappus bristles 20-30 mm long (vs. C. discolor, with leaf blades glabrate or sparsely villous on the adaxial surface, stems glabrate or with some tomentum near the apex, and pappus bristles 18-25 mm long).
Cirsium altissimum:
stem leaf blades with flat margins, unlobed or with short lobes, and tips of innermost involucral bracts dilated and erose to serrulate (vs. C. discolor, with stem leaf blades with revolute margins and evident narrow lobes, and tips of innermost involucral bracts slender, not dilated, and entire).

Synonyms

  • Carduus discolor (Muhl. ex Willd.) Nutt.

Family

Asteraceae

Genus

Cirsium