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- Dichotomous Key
- Asteraceae
- Asteraceae Group 5
- Jacobaea
- Jacobaea vulgaris
Jacobaea vulgaris — tansy ragwort
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Facts
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
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
-
- 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
-
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)
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- present, invasive, prohibited
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
1. Jacobaea vulgaris Gaertn. E
tansy ragwort. Senecio jacobaea L. • MA, ME. Fields, pastures, roadsides.