Cirsium palustre (L.) Scop.

marsh thistle

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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

A European native, and highly invasive in North America, marsh thistle can displace native wetland flora as it forms dense stands. Its range is currently limited, but it is rapidly expanding.

Habitat

Marshes, swamps, wetland margins (edges of wetlands)

Characteristics

Habitat
wetlands
New England state
  • Massachusetts
  • New Hampshire
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 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
150–300 mm
Disk flower number
  • 21-50
  • more than 50
Show All Characteristics
  • Flowers
    Bract color
    the bracts are colored, or at least 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
    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 ovate (egg-shaped)
    Bract spines
    • the bracts have no 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 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)
    Bracts
    there are at least two distinct forms of bracts in different cycles
    Disk flower number
    • 21-50
    • more than 50
    Disk flower reproductive parts
    • the disk flower has both pollen- and seed-producing parts
    • the disk flower has either only pollen- or only 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
    • 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 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
    10–20 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 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
    Peduncle length
    0–10 mm
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Ray length
    0 mm
    Reproductive system
    • all the flowers on some plants have carpels, while all the flowers on other plants have stamens
    • all the flowers on the plant contain both carpels and stamens
    Scale tip
    NA
    Style branch number
    the style has two branches
    Width of flower head base
    8–13 mm
  • Fruits or seeds
    Ovary length in developed fruit
    2.5–3.5 mm
    Seed hair tuft details
    the pappus hairs have smaller hairs along their sides
    Seed hair tuft length
    9–11 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
  • 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
    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 edges
    • the edge of the leaf blade has lobes, or it has both teeth and lobes
    • the edge of the leaf blade has teeth
    Leaf blade hairs
    • the leaf blade has simple hairs with no glands, and not tangled or wooly
    • the leaf blade has tangled or woolly-looking hairs
    Leaf blade length
    150–300 mm
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    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
    30–100 mm
    Leaf disposition
    the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
    Leaf spines
    there are spines along the leaf edges
    Leaf stalk
    • the leaves have leaf stalks
    • the leaves have no leaf stalks, but attach directly to the stem
    Leaf tip extension
    NA
    Leaf type
    leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Specific leaf type
    • the leaf has a row of two or more lobes on each side of the central axis
    • the leaves are simple (i.e., lobed or unlobed but not separated into leaflets
  • Place
    Habitat
    wetlands
    New England state
    • Massachusetts
    • New Hampshire
    Specific habitat
    • edges of wetlands
    • marshes
    • swamps
  • 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 are tangled, matted or woolly
    Stem internode hairs
    the stem has hairs between the nodes
    Stem wings
    the stem has wings on it that run down the stem from the leaf nodes

Wetland Status

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

New England Distribution and Conservation Status

Distribution

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

Conservation Status

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

Massachusetts
not applicable (S-rank: SNA)

Native to North America?

No

Sometimes Confused With

Cirsium vulgare

Synonyms

  • Carduus palustris L.

Family

Asteraceae

Genus

Cirsium

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Information from Dichotomous Key of Flora Novae Angliae

7.  Cirsium palustre (L.) Scop. E

marsh thistle. Carduus palustris L. • MA, NH. Marshes, swamp edges, low clearings.