Canada Thistle, Creeping Thistle
Cirsium arvense
Synonyms: Cirsium arvense var. arvense, Cirsium arvense var. horridum, Cirsium arvense var. mite
Canada thistle as seen along Road #16 at Summit Prairie, Malheur National Forest............August 20, 2011.
Close-up of the involucral bracts of Canada thistle as seen along Road #16 at Summit Prairie, Malheur National Forest.........August 20, 2011.
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Close-ups of the inflorescence and a leaf of Canada thistle as seen along Road #23 at the Mt.
Adams viewpoint at the southwestern corner of Mt. Adams..........August
6, 2005.
A view of Canada thistle as seen along forest road #3521 in the Wenatchee National Forest.........August 13, 2009.
A large patch of Canada thistle blooming along the trail around Walton Lake, Ochoco National Forest...........August 8, 2014. Note the large number of fritillaries that have been attracted to the thistles.
Paul Slichter