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Native Plant Trust: Go Botany Discover thousands of New England plants

Helianthus debilis — weak sunflower

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Facts

Cucumber-leaved sunflower has been recorded throughout New England, but this is probably outside its native range of eastern and southeastern states. It inhabits fields, roadsides and waste areas.

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
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
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
  • opposite: there are two leaves 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
  • 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
Ray flower color
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
25–140 mm
Disk flower number
21-50
Show all characteristics
  • Flowers

    Bract cycle number
    • there are three or more cycles of bracts
    • there are two main cycles of bracts
    Bract margins
    • there are few or no fine hairs along the 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 shape
    the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
    Bract spines
    the bracts have no spines
    Bract tip orientation
    the bracts are pressed against the plant, or spreading out at the tips
    Bract tip shape
    the tips of the bracts are acuminate (tapered to a narrow point)
    Bracts
    the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
    Disk flower color
    • blue to purple
    • pink to red
    Disk flower number
    21-50
    Disk flower reproductive parts
    the disk flower has both pollen- and seed-producing parts
    Disk width
    16–20 mm
    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 papery scales on it
    Flower head profile
    the disk is flat or nearly flat across the top
    Flower type in flower heads
    • the flower head has disk flowers only, and lacks the strap-shaped flowers
    • 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
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
    Ovary beak
    there is no beak on the ovary
    Ovary cross-section
    the ovary is compressed (flattened)
    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
    Ray flower color
    yellow
    Ray flower reproductive parts
    there are neither carpels nor stamens in the ray flowers
    Ray flowers
    • 11-15
    • 16-25
    Ray length
    30–60 mm
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    Style branch number
    the style has two branches
    Style branches
    the style branch is wider at the tip and has a flattened end, or the style branches are wider at the tips and have flattened ends
    Width of flower head base
    20–25 mm
  • Fruits or seeds

    Number of pappus parts
    2
    Ovary length in developed fruit
    2.5–3.2 mm
    Seed hair tuft bases
    NA
    Seed hair tuft color
    NA
    Seed hair tuft details
    NA
    Seed hair tuft length
    1–5 mm
    Seed hair tuft tips
    NA
    Seed hairs uniform
    NA
    Seed tuft scale number
    2–6
    Seed tuft type
    • the pappus is made of flat scales that are not split or frayed at the tips
    • the pappus is made of stiff, tapering bristles
    Top of disk flower ovary
    NA
    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

    Leaf blade glands
    • the leaf blades have glandular (translucent) dots or scales
    • the leaf blades have no glandular (translucent) dots or scales
  • 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
    Underground organs
    there are only slender roots on the plant
  • Leaves

    Hairs on underside of leaf blade
    the underside of the leaf is fuzzy or hairy
    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
    • 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)
    • the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
    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
    25–140 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)
    • the leaf blade is triangular, with the stalk or attachment point on one of the sides
    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 three main veins running from the base towards the tip
    Leaf blade width
    15–90 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
    30–60 mm
    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
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    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 direction
    the hairs point mostly upwards to outwards
    Stem internode hairs
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes

Wetland status

Occurs only in non-wetlands. (Wetland indicator code: UPL)

In New England

Distribution

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

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

ssp. cucumerifolius

Massachusetts
not applicable (S-rank: SNA)
Vermont
not applicable (S-rank: SNA)

Subspecies and varieties

Our subspecies is Helianthus debilis Nutt. ssp. cucumerifolius.

From Flora Novae Angliae dichotomous key

2.  Helianthus debilis Nutt. ssp. cucumerifolius (Torr. & Gray) Heiser E

weak sunflower. Helianthus cucumerifolius Torr. & Gray; H. debilis Nutt. var. cucumerifolius (Torr. & Gray) Gray • CT, MA, ME, NH, RI, VT. Roadsides, fields, waste areas.

Native to North America?

Yes and no (some introduced)

Sometimes confused with

Helianthus petiolaris:
chaff near the center of the disk conspicuously pubescent near the apex with long, white hairs, cypselas not mottled, pubescent with appressed-ascending hairs and leaf blades pale green and strigose (vs. H. debilis, with chaff near the center of the disk inconspicuously short-pubescent, cypselas mottled, pubescent with spreading-ascending hairs, and leaf blades dark green and scabrous).

Synonyms

  • Helianthus cucumerifolius Torr. & Gray
  • Helianthus debilis Nutt. var. cucumerifolius (Torr. & Gray) Gray

Family

Asteraceae

Genus

Helianthus