Jacobaea vulgaris Gaertn.

tansy ragwort

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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

Tansy ragwort is considered a noxious weed in California and the Northwest, but it is rare in New England. It was first seen in seaports in the early 1900's, and is easily spread in contaminated hay. It is a cause of toxins in milk as cattle do not avoid it.

Habitat

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

Characteristics

Habitat
terrestrial
New England state
  • Maine
  • Massachusetts
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
Leaf blade edges
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
  • the flower head has ray flowers only, meaning all of the individual flowers of the flower head have a strap-shaped ray, which may or may not have teeth at the very tip of the ray
Ray flower color
yellow
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
40–300 mm
Flower head width
15–20 mm
Disk flower number
  • 1-5
  • more than 50
Show All Characteristics
  • Flowers
    Bract cycle number
    there is one main cycle 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 separation
    the bracts appear completely unconnected to one another on all flower heads
    Bract shape
    the main bracts are ovate (egg-shaped)
    Bract spines
    the bracts have no spines
    Bract texture
    the bracts appear thin, flexible and nearly translucent
    Bract tip color
    the tips are a different color from the center of the bract
    Bract tip shape
    the tips of the bracts acute (have a sharp point)
    Bract width
    At least 1.2
    Bracts
    the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
    Disk flower color
    yellow
    Disk flower lobe number
    5
    Disk flower number
    • 1-5
    • 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
    • the disk flower looks different from the choices given
    Disk width
    7–10 mm
    Flower head number
    each flowering stem has four or more flower heads on it
    Flower head outer flowers
    at the outer edge of the flower head, each flower has a single enlarged lobe or strap
    Flower head platform
    the base has no bristles or papery scales
    Flower head profile
    • the disk is flat or nearly flat across the top
    • the disk is rounded across the top
    Flower head shape
    the flower head is shaped like a cone with the point up
    Flower head width
    15–20 mm
    Flower type in flower heads
    • the flower head has disk flowers only, and lacks the strap-shaped flowers
    • the flower head has ray flowers only, meaning all of the individual flowers of the flower head have a strap-shaped ray, which may or may not have teeth at the very tip of the ray
    Height of flower head base
    3–5 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the inflorescence is flat-topped in profile
    Inflorescence stem
    hairs are present on the stem of the inflorescence
    Number of bracts at flower head base
    12–14
    Ovary cross-section
    the ovary has five or more corners in cross-section
    Ovary hair type
    • the ovary has hairs on it, but the hairs have no glands
    • the ovary has no hairs on it
    Ovary hairs
    • the ovary has hairs on it
    • the ovary has no hairs on it
    Ovary lines or ribs
    there are four to six lines or ribs visible on the ovary
    Ovary profile
    in profile, the ovary is oblong (roughly rectangular but rounded at the ends)
    Ray flower color
    yellow
    Ray flower reproductive parts
    the ray flowers have carpels or stamens, but not both
    Ray flowers
    • 0
    • 11-15
    Ray length
    4–8 mm
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    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
    5–40 mm
  • Fruits or seeds
    Number of pappus parts
    11 or more
    Ovary length in developed fruit
    2–3 mm
    Seed hair tuft color
    the pappus hairs are white or off-white
    Seed hair tuft details
    • the pappus hairs are hooked or barbed
    • the pappus hairs are smooth and plain
    Seed hair tuft tips
    the pappus hairs are slender
    Seed tuft type
    the pappus is made of very fine hairs or bristles
    Tuft or plume on fruit
    at least a part of the plume is made up of fine bristles
  • 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
    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 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 teeth
    Leaf blade hairs
    the leaf blade has tangled or woolly-looking hairs
    Leaf blade length
    40–300 mm
    Leaf blade shape
    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 obtuse (bluntly pointed)
    • the tip of the leaf blade is rounded, with no point
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    Leaf blade width
    10–120 mm
    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
    • the leaves have no leaf stalks, but attach directly to the stem
    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, and each lobe itself has rows of lobes on each side of the lobe's central axis
    • the leaf has lobes that themselves have lobes, and these secondary lobes also have lobes; there may be more than three levels of lobes
  • Place
    Habitat
    terrestrial
    New England state
    • Maine
    • Massachusetts
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • Scent
    Plant odor
    the plant has an unpleasant or repellant odor
  • 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
    • the stem has no hairs between the nodes
    Stem internode hairs
    the stem has hairs between the nodes

Wetland Status

Occurs only in non-wetlands. (Wetland indicator code: UPL)

New England Distribution and Conservation Status

Distribution

Connecticut
absent
Maine
present
Massachusetts
present, invasive, prohibited
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation Status

None

Native to North America?

No

Synonyms

  • Senecio jacobaea L.

Family

Asteraceae

Genus

Jacobaea

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Information from Dichotomous Key of Flora Novae Angliae

1.  Jacobaea vulgaris Gaertn. E

tansy ragwort. Senecio jacobaea L. • MA, ME. Fields, pastures, roadsides.