Scientific Name: Carduus acanthoides

Common Name: spiny plumeless thistle

Other Common Names: plumeless thistle, carduus thistle

Habit: Upright, growing from a taproot

Leaves: Leaves are arranged in a rosette at the base of the plant and alternate going up the stem. Leaf margins are serrate or pinnately lobed and leaves can be 4 to 8 in long and up to 3 in wide. Leaves are typically smooth on the underside.

Identifying Characteristics: This species is marked by spiny, winged stems. Overall, it is similar to musk thistle but typically differs in having smaller leaves and flowers and has an erect, winged peduncle.

Flower Seed Head: Flowers can be about an inch in diameter and exist alone at the end of a straight peduncle. Spiny bracts and a receptacle that is close to half the length of the flower characterize this species.

Seed Fruit: Achenes are flat ovals with a long pappus.

Where Found: This is common in disturbed areas like fields, roadsides, stream banks, and pastures.

  • Life cycle: biennial

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Present

  • Plant family: Asteraceae

  • Leaf arrangement: alternate; rosette

  • Leaf shape: lance; spatulate; triangle

  • Ochrea: Not Present

  • Leaf margin: lobed; serrated

  • Stem hairs: no hairs

  • Flower color: purple; pink

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: no hairs; has hairs

  • Flower symmetry: radial symetery

  • Flower diameter: quarter; nickle; dime

  • Root structure: taproot

  • Leaf stalk: none