Italian thistle, <i>Carduus pycnocephalus,</i> has groups of 2 to 5 flower heads at the tops of stems, and its stem wings are less continuous near the flower heads.
Italian thistle, Carduus pycnocephalus, has groups of 2 to 5 flower heads at the tops of stems, and its stem wings are less continuous near the flower heads.
Credit: Joseph M. DiTomaso