Canada Thistle (Cirsium arvense).  Thistles are covered more extensively in the Prairie Plants section.Canada Thistle (Cirsium arvense)

Canada Thistle (Cirsium arvense)

Musk or Nodding Thistle  (Carduus nutans).Musk Thistle (Carduus nutans)

Musk or Nodding Thistle

Musk Thistle ready to bloom.Musk Thistle (Carduus nutans) Starting to Bloom

Thistles are a biennial plant.   The first year only a rosetta, as below, grows.Musk Thistle 1st-year Rosetta

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