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- Carduus acanthoides
Carduus acanthoides — spiny plumeless-thistle
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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.
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Facts
This non-native species is considered a noxious weed and prohibited in many states across the country. It is a very spiny species, and spreads rapidly by producing many thousands of seeds per plant.
Habitat
Anthropogenic (man-made or disturbed habitats), meadows and fields
Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- Rhode Island
- Vermont
- Leaf type
- leaves are simple (lobed or unlobed but not separated into leaflets)
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade edges
- the edge of the leaf blade has lobes, or it has both teeth and lobes
- 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
- 100–300 mm
- Flower head width
- 18–25 mm
-
Flowers
- Bases of bract appendages
- NA
- 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 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
- Bract tip extension edge
- there are projections from the bract tips
- 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)
- Bract width
- 1–2
- Disk flower color
-
- blue to purple
- white
- Disk flower lobe number
- 5
- Disk flower reproductive parts
- the disk flower has both pollen- and seed-producing parts
- Disk flower shape
-
- the disk flower is abruptly widened at some point below the lobes
- the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel
- Disk width
- 15–25 mm
- 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 conical across the top
- the disk is flat or nearly flat across the top
- the disk is rounded across the top
- Flower head shape
- the flower head is hemispherical (like the bottom half of a sphere)
- Flower head width
- 18–25 mm
- Flower type in flower heads
- the flower head has disk flowers only, and lacks the strap-shaped flowers
- Height of flower head base
- 14–20 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
- the ovary is attached at the side near the base, rather than at 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 oblong (roughly rectangular but rounded at the ends)
- in profile, the ovary is roughly egg-shaped
- in profile, the ovary is roughly egg-shaped, but widest above the middle
- Ovary surface
- the ovary surface has no points, bumps or wrinkles, though it may have lines, ribs or wings
- Peduncle length
- Up to 100 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
- 10–25 mm
-
Fruits or seeds
- Number of pappus parts
- 11 or more
- Ovary length in developed fruit
- 2.5–3 mm
- Seed hair tuft bases
- the pappus hairs are attached to one another near the base
- 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
- 11–13 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 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 annual, it lacks evidence of previous years' growth
- the plant is biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit
- Spines on plant
- there are spines on the plant
- Underground organs
- 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
- 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
- Leaf blade base
-
- the leaf has a distinct petiole
- the leaf has no petiole
- 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
- 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
- 100–300 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 surface colors
- there is no noticeable color variation on the upper surface of the leaf
- Leaf blade veins
- the leaf blade has one main vein running from the base towards the tip
- Leaf blade width
- 20–80 mm
- Leaf disposition
-
- the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
- 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 stalk length
- At least 0 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 leaf has a row of two or more lobes on each side of the central axis
- the leaf has a row of two or more lobes on each side of the central axis, and each lobe itself has rows of lobes on each side of the lobe's central axis
-
Place
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- 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 hair direction
- 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
- Stem internode hairs
-
- the stem has hairs between the nodes
- the stem has no hairs between the nodes
- Stem wings
- the stem has wings on it that run down the stem from the leaf nodes
Wetland status
Not classified
New England distribution and conservation status
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- present
- 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
- Carduus crispus:
- undersurface of leaves with two types of hairs: longer, curling, septate hairs on the veins and sparse, woolly hairs inbetween (vs. C. anthoides, with the undersurface of leaves with only type of hair: curling and septate).
Family
Genus
Notes on subspecies and varieties in New England
Our subspecies is Carduus acanthoides L. ssp. acanthoides.
From the dichotomous key of Flora Novae Angliae
1. Carduus acanthoides L. ssp. acanthoides E
spiny plumeless-thistle. CT, MA, ME, RI, VT. Roadsides, fields, pastures.