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• Dichotomous Key
• Asteraceae
• Asteraceae Group 4
• Cosmos
• Cosmos sulphureus

Cosmos sulphureus — sulphur cosmos

Facts

Sulphur cosmos is native to Mexico and introduced around the world. It is a popular garden annual, with several cultivars. It is recorded from Connecticut and Massachusetts.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract cycle number

  there are two main cycles of bracts

  Bract outer side hair type

  • the bracts are hairy, with simple hairs on their outer surface
  • the bracts are not hairy on their outer surface

  Bract outer side hairs

  • the bracts are hairy on their outer surfaces
  • the bracts are not 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 oblong (roughly rectangular but rounded at the ends)

  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 color

  • the tips are a different color from the center of the bract
  • the tips are the same color as the center of the bract

  Bract tip orientation

  the bracts are pressed against the plant, or spreading out at the tips

  Bract tip shape

  • the tips of the bracts acute (have a sharp point)
  • 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

  • orange
  • yellow

  Disk flower lobe number

  5

  Disk flower number

  • 11-20
  • 21-50
  • 6-10
  • 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 four or more flower heads on it
  • 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

  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
  • some or all the flower heads are grouped in clusters of two or more

  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)
  • 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

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  • NA
  • the inflorescence is flat-topped in profile

  Ovary beak

  there is a 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
  • the ovary has no hairs on it

  Ovary hairs

  • the ovary has hairs on it
  • the ovary has no hairs on it

  Ovary profile

  in profile, the ovary is another shape

  Peduncle hair type

  the hairs on the peduncles are simple (not branched), don’t have glands, and are not woolly

  Peduncle hairs

  • the peduncles are hairy
  • the peduncles have no hairs

  Peduncle length

  100–200 mm

  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
  • 6-10

  Ray length

  18–30 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

  6–10 mm

• Fruits or seeds

  Number of pappus parts

  • 0
  • 2

  Ovary length in developed fruit

  15–30 mm

  Seed hair tuft bases

  NA

  Seed hair tuft color

  NA

  Seed hair tuft details

  NA

  Seed hair tuft length

  0–7 mm

  Seed hair tuft tips

  NA

  Seed hairs uniform

  NA

  Seed tuft scale number

  0–2

  Seed tuft type

  the pappus is made of stiff, tapering bristles

  Top of disk flower ovary

  NA

  Tuft or plume on fruit

  • NA
  • 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

• Leaves

  Final leaf segment width (compound lvs only)

  2–5 mm

  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

  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 edges

  the edge of the leaf blade has lobes, or it has both teeth and lobes

  Leaf blade hairs

  NA

  Leaf blade length

  50–250 mm

  Leaf blade shape

  the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)

  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 rounded, with no point

  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
  • the leaf has a row of two or more lobes on each side of the central axis, and each lobe itself has rows of lobes on each side of the lobe's central axis
  • the leaf has lobes that themselves have lobes, and these secondary lobes also have lobes; there may be more than three levels of lobes

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Massachusetts

  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 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

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae