Centaurea scabiosa L.

greater knapweed

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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

Greater knapweed is native to Europe and occasionally escapes from cultivation in some parts of North America. Its large flowers make it a popular garden ornamental, and it is also used in traditional medicine to treat kidney problems, mouth ulcers, and to aid the healing of wounds.

Habitat

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

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • 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 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
  • blue to purple
  • pink to red
  • white
Tuft or plume on fruit
at least a part of the plume is made up of fine bristles
Spines on plant
the plant has no spines
Leaf blade length
100–250 mm
Flower head width
50–60 mm
Show All Characteristics
  • Flowers
    Bases of bract appendages
    bases of bract appendages are u-shaped, with a tiny projecting edge running across from one appendage to the next
    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, with simple hairs on their outer surface
    • the bracts are not hairy on their outer surface
    Bract outer side hairs
    • the bracts are hairy on their outer surfaces
    • the bracts are not 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 oblong (roughly rectangular but rounded at the ends)
    • the main bracts are ovate (egg-shaped)
    Bract spines
    the bracts have no spines
    Bract tip color
    the tips are a different color from the center of the bract
    Bract tip extension appearance
    the projections from the bract tips have further projections from their edges, like a fringe
    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
    NA
    Bract width
    3–4
    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 lobe number
    5
    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 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, but are bigger than the flowers 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
    Flower head shape
    the sides of the flower head are roughly parallel, like a cylinder
    Flower head width
    50–60 mm
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    15–25 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the inflorescence is flat-topped in profile
    Ovary attachment
    the ovary is attached at the side near the base, rather than at the base
    Ovary beak
    there is no beak on the ovary
    Ovary cross-section
    • the ovary has five or more corners in cross-section
    • the ovary is compressed (flattened)
    Ovary hair type
    the ovary has hairs on it, but the hairs have no glands
    Ovary hairs
    the ovary has hairs on it
    Ovary profile
    • in profile, the ovary is oblong (roughly rectangular but rounded at the ends)
    • in profile, the ovary is roughly elliptical (widest in the middle, tapering to both ends)
    Ray flower color
    • blue to purple
    • pink to red
    • white
    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
    Style branch number
    the style has two branches
    Width of flower head base
    18–25 mm
  • Fruits or seeds
    Ovary length in developed fruit
    4–5.5 mm
    Seed hair tuft color
    the pappus hairs are white or off-white
    Seed hair tuft length
    3–6 mm
    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 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 perennial, it shows evidence of previous year's leaves, stems or stem bases
    Spines on plant
    the plant has no spines
    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
    • basal: the leaves are growing only at the base of the plant
    Leaf blade base
    the leaf has a distinct 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 no teeth or lobes
    • the edge of the leaf blade has teeth
    Leaf blade hairs
    • the leaf blade has hairs with glands at their tips
    • the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    100–250 mm
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is oblong (rectangular but with rounded ends)
    • 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 acute (sharply pointed)
    • the tip of the leaf blade is obtuse (bluntly pointed)
    Leaf disposition
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have leaf stalks
    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 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
    • New Hampshire
    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
    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
    • the stem has no hairs between the nodes

Wetland Status

Not classified

New England Distribution and Conservation Status

Distribution

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

Conservation Status

None

Native to North America?

No

Sometimes Confused With

Centaurea stoebe:
involucre 6-8 mm wide, the bracts with several prominent longitudinal veins, and fertile flowers 12-15 mm long (vs. C. scabiosa, with the involucre 18-25 mm wide, the bracts lacking prominent longitudinal veins, and fertile flowers 20-25 mm long).

Synonyms

  • Acrocentron scabiosa (L.) A. & D. Löve
  • Colymbada scabiosa (L.) Holub

Family

Asteraceae

Genus

Centaurea

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Information from Dichotomous Key of Flora Novae Angliae

11.  Centaurea scabiosa L. E

greater knapweed. Acrocentron scabiosa (L.) A. & D. Löve; Colymbada scabiosa (L.) Holub 
• CT, ME, NH. Roadsides, fields, waste areas.