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Bidens pilosa — hairy beggar-ticks

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Facts

Hairy beggar-ticks is native to tropical America, and has become a major weed and pest species worldwide. It can form dense stands and its seeds contaminate food crops. Furthermore, it is a host and vector for crop diseases such as root knot nematode (Meloidogyne sp.) and tomato spotted wilt virus (Schlerotinia sclerotiorum).

Habitat

Anthropogenic (man-made or disturbed habitats)

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
Connecticut
Leaf type
leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
opposite: there are two leaves per node along the stem
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 teeth
Flower type in flower heads
  • the flower head has disk flowers only, and lacks the strap-shaped flowers
  • the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
Ray flower color
  • white
  • yellow
Tuft or plume on fruit
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
30–120 mm
Flower head width
5–15 mm
Disk flower number
  • 11-20
  • 21-50
  • more than 50
Show all characteristics
  • Flowers

    Bases of bract appendages
    NA
    Bract cycle number
    there are two main 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
    Bract outer side hairs
    the bracts are hairy on their outer surfaces
    Bract separation
    • at least some flower heads have bracts connected to one another at or near their bases
    • the bracts appear completely unconnected to one another on all flower heads
    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 oblanceolate (widest near the tip, but otherwise narrow and tapering)
    • the main bracts are of a different shape than the given options
    Bract spines
    the bracts have no spines
    Bract texture
    • the bracts appear thin, flexible and nearly translucent
    • the bracts have a similar texture to a leaf
    Bract tip orientation
    the bracts are pressed against the plant, or spreading out at the tips
    Bracts
    there are at least two distinct forms of bracts in different cycles
    Disk flower color
    yellow
    Disk flower lobe number
    • 3
    • 4
    • 5
    Disk flower number
    • 11-20
    • 21-50
    • 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
    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, each flower has a single enlarged lobe or strap
    • 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 papery scales on it
    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
    • the disk is rounded across the top
    Flower head shape
    • the flower head is shaped like a cone with the point up
    • the sides of the flower head are roughly parallel, like a cylinder
    Flower head width
    5–15 mm
    Flower type in flower heads
    • the flower head has disk flowers only, and lacks the strap-shaped flowers
    • the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
    Height of flower head base
    5–6 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    • NA
    • the inflorescence is flat-topped in profile
    Number of bracts at flower head base
    13–26
    Ovary beak
    there is no beak on the ovary
    Ovary cross-section
    • the ovary is compressed (flattened)
    • the ovary is roughly square or with four corners
    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 another shape
    • in profile, the ovary is very narrow
    Ovary surface
    the ovary surface is textured with tiny points, bumps or wrinkles
    Peduncle length
    10–90 mm
    Ray flower color
    • white
    • yellow
    Ray flower reproductive parts
    there are neither carpels nor stamens in the ray flowers
    Ray flowers
    • 0
    • 1-5
    • 6-10
    Ray length
    0–5 mm
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    Scale tip
    the scales are blunt, with a terminal notch, or straight across the top
    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
    6–8 mm
  • Fruits or seeds

    Number of pappus parts
    • 2
    • 3
    • 4
    • 5
    Ovary beak length
    0 mm
    Ovary length in developed fruit
    3–16 mm
    Seed hair tuft details
    the pappus hairs are hooked or barbed
    Seed hair tuft length
    0–4 mm
    Seed hair tuft tips
    the pappus hairs are slender
    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 stiff, tapering bristles
    Top of disk flower ovary
    the top of the ovary in fruit is flattened
    Tuft or plume on fruit
    there is no plume, or the plume is made up of scales, awns, a crown, or a rim
  • Glands or sap

    Bract resin
    the bracts have no resin or resin glands
    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 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

    Final leaf segment length (compound lvs only)
    10–80 mm
    Final leaf segment width (compound lvs only)
    5–40 mm
    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
    opposite: there are two leaves per node along the stem
    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
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    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 teeth
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    30–120 mm
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both 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 acuminate (tapers to a long, thin point)
    • the tip of the leaf blade is acute (sharply pointed)
    Leaf blade width
    12–45 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
    Leaf stalk length
    10–70 mm
    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
  • Place

    Habitat
    terrestrial
    New England state
    Connecticut
    Specific habitat
    man-made or disturbed habitats
  • 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 direction
    NA
    Stem internode hair length
    0 mm
    Stem internode hair type
    the stem has no hairs between the nodes
    Stem internode hairs
    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
present
Maine
absent
Massachusetts
absent
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation status

None

From Flora Novae Angliae dichotomous key

12.  Bidens pilosa L. E

hairy beggar-ticks. Bidens odorata Cav.; B. pilosa L. var. minor (Blume) Sherff • CT. Ballast, waste areas.

Native to North America?

No

Sometimes confused with

Bidens alba:
capitula with 5-8 ray flowers with well developed rays 5-16 mm long and involucral bracts numbering mostly 12 (vs. B. pilosa, with capitula without ray flowers or with short rays up to 3 mm and involucral bracts numbering 7-10).

Synonyms

  • Bidens odorata Cav.
  • Bidens pilosa L. var. minor (Blume) Sherff

Family

Asteraceae

Genus

Bidens