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Vernonia fasciculata — prairie ironweed

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Facts

Prairie ironweed, as the name suggests, is native to the grasslands of the midwest. It is grown as an ornamental plant, for its dramatic height and purple flowers. Prairie ironweed has been collected in Massachusetts, but does not commonly escape from New England gardens.

Habitat

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

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
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
Ray flower color
NA
Tuft or plume on fruit
  • at least a part of the plume is made up of fine bristles
  • there is no plume, or the plume is made up of scales, awns, a crown, or a rim
Spines on plant
the plant has no spines
Leaf blade length
50–200 mm
Disk flower number
  • 11-20
  • 21-50
Show all characteristics
  • Flowers

    Bases of bract appendages
    NA
    Bract color
    the bracts are colored, or at least tinged with, pink, red or purple
    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 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 linear (long and very narrow)
    • the main bracts are oblong (roughly rectangular but rounded at the ends)
    • the main bracts are ovate (egg-shaped)
    Bract tip extension appearance
    NA
    Bract tip extension edge
    NA
    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)
    • the tips of the bracts are obtuse (have a blunt point)
    • the tips of the bracts are rounded
    Disk flower color
    • blue to purple
    • pink to red
    • white
    Disk flower number
    • 11-20
    • 21-50
    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
    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, 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 no bristles or papery scales
    Flower head platform surface
    NA
    Flower head position
    some or all the flower heads are grouped in clusters of two or more
    Flower head profile
    • the disk is flat or nearly flat across the top
    • the disk is rounded across the top
    Flower head shape
    the sides of the flower head are roughly parallel, like a cylinder
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    5–8 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
    25–35
    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 seven to nine ribs visible on the ovary
    • there are ten or more ribs visible on the ovary
    Ovary profile
    in profile, the ovary is oblong (roughly rectangular but rounded at the ends)
    Peduncle length
    1–12 mm
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    NA
    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
    Style branches
    the style branch is narrow at the tip, or the style branches are narrow at the tips
    Width of flower head base
    4–6 mm
  • Fruits or seeds

    Number of pappus parts
    11 or more
    Ovary length in developed fruit
    3.5–4 mm
    Seed hair tuft color
    the pappus hairs are another color
    Seed hair tuft length
    0.5–7 mm
    Seed hair tuft tips
    the pappus hairs are slender
    Seed hairs uniform
    there are two distinct lengths of pappus hairs
    Seed tuft scale number
    20–30
    Seed tuft type
    • the pappus is made of flat scales that are not split or frayed at the tips
    • 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
    • there is no plume, or the plume is made up of scales, awns, a crown, or a rim
  • Glands or sap

    Leaf blade glands
    the leaf blades have glandular (translucent) dots or scales
    Ovary glands
    there are glands on the ovary surface
    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
    • the plant has a rhizome (a horizontal underground stem with roots growing from it)
    • there are only slender roots on the plant
  • Leaves

    Hairs on underside of leaf blade
    • the underside of the leaf is fuzzy or hairy
    • the underside of the leaf is not hairy, or has very few hairs
    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 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 simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    50–200 mm
    Leaf blade shape
    the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    Leaf blade surface colors
    there is no noticeable color variation on the upper surface of the leaf
    Leaf blade tip
    • the tip of the leaf blade is acuminate (tapers to a long, thin point)
    • the tip of the leaf blade is acute (sharply pointed)
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    Leaf blade width
    5–40 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 no leaf stalks, but attach directly to the stem
    Leaf tip extension
    NA
    Leaf type
    leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets
  • Place

    Habitat
    terrestrial
    New England state
    Massachusetts
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
  • 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 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

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

In New England

Distribution

Connecticut
absent
Maine
absent
Massachusetts
present
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.  Vernonia fasciculata Michx. E

prairie ironweed. MA. Fields, roadsides, waste areas.

Native to North America?

Yes and no (some introduced)

Sometimes confused with

Vernonia missurica:
abaxial surface of leaf blades thinly to densely tomentose, the pubescence usually concealing the puncta, and capitula with mostly 32–55 flowers (vs. V. fasciculata, with abaxial surface of leaf blades +/- glabrous and conspicuously punctate and capitula with mostly 12–25 flowers).

Family

Asteraceae

Genus

Vernonia