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• Flaveria trinervia

Flaveria trinervia — clustered yellowtops

Facts

Clustered yellowtops is a plant mainly of the southwestern states and Mexico, but has become invasive in many parts of the world. It grows on saline and other mineralized soils, and is an exceptional bioaccumulator of arsenic. It has been tested for use in bioremediation of contaminated mine tailings.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

• Flowers

  Bract cycle number

  there is one main cycle of bracts

  Bract outer side hair type

  the bracts are not hairy on their outer surface

  Bract outer side hairs

  the bracts are not hairy on their outer surfaces

  Bract shape

  the main bracts are oblong (roughly rectangular but rounded at the ends)

  Bract spines

  the bracts have no spines

  Bract tip shape

  the tips of the bracts are obtuse (have a blunt point)

  Bracts

  NA

  Disk flower color

  yellow

  Disk flower lobe number

  5

  Disk flower number

  • 0
  • 1-5

  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, 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 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 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 tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery

  Height of flower head base

  3.8–4.5 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  • the flower heads grow in clusters from the axils of the branches or leaves
  • the inflorescence is flat-topped in profile

  Inflorescence stem

  the stem of the inflorescence is not hairy

  Number of bracts at flower head base

  2

  Ovary cross-section

  the ovary is compressed (flattened)

  Ovary hair type

  the ovary has no hairs on it

  Ovary hairs

  the ovary has no hairs on it

  Ovary lines or ribs

  there are ten or more ribs visible on the ovary

  Ovary profile

  • in profile, the ovary is another shape
  • in profile, the ovary is lance-shaped, but widest above the middle

  Peduncle hair type

  NA

  Peduncle hairs

  NA

  Peduncle length

  0 mm

  Peduncle orientation

  NA

  Ray flower color

  yellow

  Ray flower reproductive parts

  • the ray flowers have carpels or stamens, but not both
  • there are neither carpels nor stamens in the ray flowers

  Ray flowers

  • 0
  • 1-5

  Ray length

  0.5–1 mm

  Reproductive system

  some of the flowers on the plant have only carpels or stamens, while others have both carpels and stamens

  Scale tip

  NA

  Smaller bracts at base of bracts

  NA

  Style branch number

  the style has two branches

  Swelling at base of flower head

  NA

  Width of flower head base

  Up to 1 mm

• Fruits or seeds

  Number of pappus parts

  0

  Ovary length in developed fruit

  2–2.6 mm

  Seed hair tuft bases

  NA

  Seed hair tuft color

  NA

  Seed hair tuft details

  NA

  Seed hair tuft length

  0 mm

  Seed hair tuft tips

  NA

  Seed hairs uniform

  NA

  Seed tuft scale number

  0

  Seed tuft type

  NA

  Top of disk flower ovary

  NA

  Tuft or plume on fruit

  NA

• Glands or sap

  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

  Spines on plant

  the plant has no spines

• Leaves

  Hairs on underside of leaf blade

  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 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
  • the leaf has no petiole
  • the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf

  Leaf blade base shape

  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 teeth

  Leaf blade hairs

  NA

  Leaf blade length

  30–150 mm

  Leaf blade shape

  • the leaf blade is elliptic (widest near the middle and tapering at both ends)
  • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
  • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
  • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)

  Leaf blade tip

  • the tip of the leaf blade is acute (sharply pointed)
  • the tip of the leaf blade is obtuse (bluntly pointed)

  Leaf blade veins

  the leaf blade has three main veins running from the base towards the tip

  Leaf blade width

  7–40 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 leaf stalks
  • the leaves have no leaf stalks, but attach directly to the stem

  Leaf stalk length

  10–20 mm

  Leaf type

  leaves are simple (i.e., lobed or unlobed but not separated into leaflets)

  Leaflet number

  0

  Specific leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  Massachusetts

  Specific habitat

  man-made or disturbed habitats

• Stem, shoot, branch

  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 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