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• Dichotomous Key
• Asteraceae
• Asteraceae Group 1
• Hieracium
• Hieracium caespitosum

Hieracium caespitosum — yellow hawkweed

Facts

Yellow hawkweed is native to Europe and was introduced as an ornamental into New York in 1879. It is now a destructive weed of pastureland. It can colonize a wide range of habitats with sandy or gravelly soils.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract outer side hair type

  the bracts are hairy on their outer surfaces, with hairs having glands (a swelling at the tip of the hair)

  Bract outer side hairs

  the bracts are hairy on their outer surfaces

  Bract tip shape

  • the tips of the bracts acute (have a sharp point)
  • the tips of the bracts are acuminate (tapered to a narrow point)

  Disk flower color

  NA

  Disk flower lobe number

  0

  Disk flower number

  0

  Disk flower proportions

  NA

  Disk flower reproductive parts

  NA

  Disk flower shape

  NA

  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 platform surface

  NA

  Flower head profile

  the disk is flat or nearly flat across the top

  Flower type in flower heads

  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

  7.5–9 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  the inflorescence is flat-topped in profile

  Number of bracts at flower head base

  12–18

  Ovary beak

  there is no beak on the ovary

  Ovary cross-section

  the ovary has five or more corners in cross-section

  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 seven to nine ribs visible on the ovary
  • there are ten or more ribs visible on the ovary

  Peduncle hair type

  • the hairs on the peduncles are branched
  • the hairs on the peduncles have glands at their tips

  Peduncle hairs

  the peduncles are hairy

  Ray flower color

  yellow

  Ray flower reproductive parts

  the ray flowers have both carpels and stamens

  Ray flowers

  • 16-25
  • 26-50
  • more than 50

  Ray length

  8–12 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 a cycle of much smaller bracts outside the cycle of larger and longer bracts

  Style branch number

  there are no obvious branches on the style

  Width of flower head base

  3–5 mm

• Fruits or seeds

  Dispersal unit

  the seeds fall off or are dispersed separately from one another

  Number of pappus parts

  11 or more

  Ovary beak length

  0 mm

  Ovary length in developed fruit

  Up to 1.5 mm

  Ovary width in developed fruit

  At least 1.8 mm

  Seed hair tuft color

  the pappus hairs are white or off-white

  Seed hair tuft details

  the pappus hairs are hooked or barbed

  Seed hair tuft length

  4–6 mm

  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 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

• Glands or sap

  Sap

  the sap is milky and opaque, and may be white or colored

• Growth form

  Growth form

  the plant has one or more free-standing stems

  Horizontal rooting stem

  • there are no stolons
  • there are stolons on some plants

  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 is a thickened taproot on the plant

• Leaves

  Final leaf segment length (compound lvs only)

  0 mm

  Final leaf segment width (compound lvs only)

  0 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

  Leaf arrangement

  • alternate: there is one leaf per node along the stem
  • the leaves are growing only at the base of the plant (basal)

  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 no teeth or lobes
  • the edge of the leaf blade has teeth

  Leaf blade hairs

  the leaf blade has branched hairs

  Leaf blade length

  35–180 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)

  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 acute (sharply pointed)
  • the tip of the leaf blade is obtuse (bluntly pointed)
  • the tip of the leaf blade is rounded, with no point

  Leaf blade width

  12–20 mm

  Leaf disposition

  the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves

  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 (lobed or unlobed but not separated into leaflets)

  Leaflet number

  0

  Specific leaf type

  the leaves are simple (lobed or unlobed but not separated into leaflets

  Teeth per side of leaf blade

  At least 0

• Place

  Habitat

  • terrestrial
  • wetlands

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields
  • shores of rivers or lakes

• Scent

  Plant odor

  the plant does not have much of an odor

• Stem, shoot, branch

  Flowering stem cross-section

  the flowering stem is circular, or with lots of small angles

  Leaves on stem

  the flowering stem has no leaves above the base

  Stem bloom

  • the stem has a powdery or waxy film on it that can be rubbed away
  • there is no powdery or waxy film on the stem

  Stem internode hair direction

  the hairs point mostly upwards to outwards

  Stem internode hair length

  1–3 mm

  Stem internode hair type

  at least some of the hairs on the stem have glands

  Stem internode hairs

  the stem has hairs between the nodes

  Stem wings

  the stem does not have wings on it

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae