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• Asteraceae Group 3
• Bidens
• Bidens pilosa

Bidens pilosa — hairy beggar-ticks

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)

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 (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)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae