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• Dichotomous Key
• Asteraceae
• Asteraceae Group 2
• Cirsium
• Cirsium altissimum

Cirsium altissimum — tall thistle

Facts

A native biennial of the United States, the natural range of tall thistle probably does not extend to New England. The Cherokee used the down to make the tails of blow darts, and an infusion of the roots to treat overeating.

Habitat

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

Characteristics

• Flowers

  Bract cycle number

  there are three or more cycles of bracts

  Bract margins

  there are few or no fine hairs along the bract margins

  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
  • the bracts are not hairy on their outer surfaces

  Disk flower number

  • 21-50
  • more than 50

  Flower head platform

  the base has fine, short hairs on it

  Flower type in flower heads

  the flower head has disk flowers only, and lacks the strap-shaped flowers

  Height of flower head base

  20–50 mm

  Ovary attachment

  the ovary is attached at or near the base

  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

  Ovary profile

  • in profile, the ovary is oblong (roughly rectangular but rounded at the ends)
  • in profile, the ovary is roughly egg-shaped, but widest above the middle

  Ovary surface

  the ovary surface has no points, bumps or wrinkles, though it may have lines, ribs or wings

  Ray flowers

  0

  Reproductive system

  • all the flowers on some plants have carpels, while all the flowers on other plants have stamens
  • some of the flowers on the plant have only carpels or stamens, while others have both carpels and stamens

  Rim at top of ovary

  the central flowers have a disk-shaped platform above the ovary

  Smaller bracts at base of bracts

  there is a cycle of much smaller bracts outside the cycle of larger and longer bracts

• Fruits or seeds

  Ovary length in developed fruit

  4–5.5 mm

  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

  Bract resin

  the bracts have resin or resin glands

  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

  there are spines on the plant

  Underground organs

  • the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • 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 not hairy, or has very few hairs

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  Leaf blade base

  • the leaf has a distinct petiole
  • 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 edges

  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has no teeth or lobes

  Leaf blade hairs

  the leaf blade has tangled or woolly-looking hairs

  Leaf blade length

  100–400 mm

  Leaf blade shape

  • the leaf blade is elliptic (widest near 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)
  • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)

  Leaf blade veins

  the leaf blade has one main vein running from the base towards the tip

  Leaf blade width

  10–60 mm

  Leaf disposition

  the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem

  Leaf spines

  there are spines along 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)

  Specific leaf type

  the leaf has a row of two or more lobes on each side of the central axis

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Massachusetts
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Stem, shoot, branch

  Leaves on stem

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

  Stem internode hair direction

  the hairs are pressed flat against the plant, pointing either towards the plant's tip or towards it's base

  Stem internode hair type

  • at least some of the hairs on the stem have glands
  • 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

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae