Silphium perfoliatum — cup-plant rosinweed

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract cycle number

  • there are three or more cycles of bracts
  • there are two main cycles of bracts

  Bract margins

  there are fine hairs along the bract margins

  Bract outer side hairs

  • the bracts are hairy on their outer surfaces
  • the bracts are not hairy on their outer surfaces

  Bract shape

  • the main bracts are elliptic (widest near the middle and tapered towards the base and tip)
  • the main bracts are ovate (egg-shaped)

  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

  yellow

  Disk flower lobe number

  5

  Disk flower number

  more than 50

  Disk flower reproductive parts

  the disk flower has either only pollen- or only seed-producing parts

  Disk width

  15–25 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 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

  12–25 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others

  Number of bracts at flower head base

  25–37

  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

  Peduncle hairs

  the peduncles are hairy

  Ray flower color

  yellow

  Ray flower reproductive parts

  the ray flowers have carpels or stamens, but not both

  Ray flowers

  • 16-25
  • 26-50

  Ray length

  15–40 mm

  Reproductive system

  the flowers on the plant may have either carpels or stamens, but always in separate flowers

  Style branch number

  the style has one branch

  Width of flower head base

  25–40 mm

• Fruits or seeds

  Ovary length in developed fruit

  8–12 mm

  Ovary width in developed fruit

  5–9 mm

  Seed hair tuft length

  0.5–1.5 mm

  Seed tuft type

  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 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 perennial, it shows evidence of previous year's leaves, stems or stem bases

  Spines on plant

  the plant has no spines

  Underground organs

  there are only slender roots 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

  Hairs on upper side of leaf blade

  the upper side of the leaf is fuzzy or hairy

  Leaf arrangement

  • opposite: there are two leaves per node along the stem
  • whorled: there are three or more leaves per node along the stem

  Leaf blade base

  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 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)

  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 length

  20–410 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 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 acuminate (tapers to a long, thin point)
  • the tip of the leaf blade is acute (sharply pointed)

  Leaf blade width

  5–240 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 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

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • shrublands or thickets

• Scent

  Plant odor

  the plant does not have much of an odor

• Stem, shoot, branch

  Flowering stem cross-section

  the flowering stem is roughly square

  Leaves on stem

  there is at least one full leaf above the base of the flowering stem

  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 length

  At least 0 mm

  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 wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

In New England

From Flora Novae Angliae dichotomous key