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- Asteraceae Group 2
- Cirsium
- Cirsium discolor
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
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
- 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
-
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.