• arvense
  • Cirsium hillii is probably most similar to C. muticum and C. arvense, but both of those species normally have more than five flowering heads, which are less than 3 cm broad, less than 3.5 cm high, and the spines on the phyllaries are less than 1 mm long. (vplants.org)
  • perennial
  • Stout, short-lived perennial from a taproot, this sometimes branching below-ground and producing more than one stem, but without the well developed creeping roots of no. 9 [Cirsium flodmanii (Rydb. (vplants.org)