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- Carduus acanthoides
Carduus acanthoides — spiny plumeless-thistle
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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
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
- 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
In New England
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)
Subspecies and varieties
Our subspecies is Carduus acanthoides L. ssp. acanthoides.
From Flora Novae Angliae dichotomous key
1. Carduus acanthoides L. ssp. acanthoides E
spiny plumeless-thistle. CT, MA, ME, RI, VT. Roadsides, fields, pastures.
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).