Cosmos bipinnatus Cav.

garden cosmos

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Garden cosmos is native to Mexico and the southwestern United States. It is an extremely popular garden ornamental, and has escaped cultivation and become naturalized in many other areas.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
Leaf type
leaves are compound (made up of two or more discrete leaflets)
Leaf arrangement
opposite: there are two leaves per node along the stem
Leaf blade edges
the edge of the leaf blade has no teeth or lobes
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
Ray flower color
  • blue to purple
  • pink to red
  • white
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
60–110 mm
Flower head width
10–15 mm
Show All Characteristics
  • Flowers
    Bases of bract appendages
    NA
    Bract cycle number
    there are two main cycles of bracts
    Bract margins
    there are few or no fine hairs along the bract margins
    Bract shape
    • the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
    • the main bracts are ovate (egg-shaped)
    Bract texture
    the bracts have a similar texture to a leaf
    Bract tip shape
    • the tips of the bracts are obtuse (have a blunt point)
    • the tips of the bracts are rounded
    Bracts
    there are at least two distinct forms of bracts in different cycles
    Disk flower color
    yellow
    Disk flower lobe number
    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
    Disk width
    10–15 mm
    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 head shape
    the flower head is hemispherical (like the bottom half of a sphere)
    Flower head width
    10–15 mm
    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
    7–15 mm
    Inflorescence branching (Solidago)
    NA
    Number of bracts at flower head base
    8
    Ovary beak
    there is a beak on the ovary
    Ovary cross-section
    the ovary is roughly square or with four corners
    Ovary hair type
    the ovary has no hairs on it
    Ovary hairs
    the ovary has no hairs on it
    Ovary profile
    in profile, the ovary is very narrow
    Ovary surface
    the ovary surface is textured with tiny points, bumps or wrinkles
    Peduncle length
    100–200 mm
    Ray flower color
    • blue to purple
    • pink to red
    • white
    Ray flower reproductive parts
    there are neither carpels nor stamens in the ray flowers
    Ray flowers
    6-10
    Ray length
    15–40 mm
    Reproductive system
    all the flowers on the plant contain both carpels and stamens
    Smaller bracts at base of bracts
    there is a cycle of much smaller bracts outside the cycle of larger and longer bracts
    Style branches
    the style branch is narrow at the tip, or the style branches are narrow at the tips
    Width of flower head base
    7–15 mm
  • Fruits or seeds
    Number of pappus parts
    • 0
    • 2
    • 3
    Ovary length in developed fruit
    7–16 mm
    Seed hair tuft bases
    NA
    Seed hair tuft color
    NA
    Seed hair tuft details
    NA
    Seed hair tuft length
    0–3 mm
    Seed hair tuft tips
    NA
    Seed hairs uniform
    NA
    Seed tuft scale number
    0
    Seed tuft type
    • the pappus is made of stiff, tapering bristles
    • there is no pappus on the ovary
    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 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
    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)
    0.5–6 mm
    Final leaf segment width (compound lvs only)
    Up to 1.5 mm
    Hairs on underside of leaf blade
    the underside 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
    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
    Leaf blade length
    60–110 mm
    Leaf blade shape
    • the leaf blade is filiform (extremely narrow, thread-like)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    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)
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    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
    0–1 mm
    Leaf tip extension
    NA
    Leaf type
    leaves are compound (made up of two or more discrete leaflets)
    Specific leaf type
    the leaf is compound, there are two or more discrete leaflets
    Teeth per side of leaf blade
    0
  • Place
    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    Specific habitat
    man-made or disturbed habitats
  • 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
    there is at least one full leaf above the base of the flowering stem
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem internode hair length
    At least 0 mm
    Stem internode hair type
    • the hairs on the stem are plain, without glands or branches, and not tangled
    • the stem has no hairs between the nodes
    Stem internode hairs
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes
    Stem wings
    the stem does not have wings on it

Wetland Status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

New England Distribution and Conservation Status

Distribution

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

Conservation Status

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

Massachusetts
not applicable (S-rank: SNA)

Native to North America?

Yes and no (some introduced)

Sometimes Confused With

Cosmos parviflorus:
rays 5-15 mm long and margins of ultimate leaf segments spinulose-ciliate (vs. C. bipinnatus, with rays 15–40 mm long and margins of ultimate leaf segments entire).

Family

Asteraceae

Genus

Cosmos

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Information from Dichotomous Key of Flora Novae Angliae

1.  Cosmos bipinnatus Cav. E

garden cosmos. CT, MA, ME, NH, RI. Roadsides, waste areas, gardens.