• hillii
  • 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)
  • Many current authorities believe this taxon is not a separate species from the eastern C. pumilum, under which it has been placed as either a subspecies or variety, still retaining the epithet hillii. (vplants.org)