Vascular Plants of North Carolina
Account for Swamp Thistle - Cirsium muticum   Michaux
Members of Asteraceae:
Members of Cirsium with account distribution info or public map:
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Section 6 » Order Asterales » Family Asteraceae
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DistributionMostly the Mountains and northern Piedmont; scattered records elsewhere in the Piedmont, and two records for the lower Coastal Plain. The Moore County record is based on a specimen at herbarium CM, collected at "Pine Bluff", but no photo is available.

Newf. to Sask., south to NC, TN, and MO.
AbundanceUncommon across the Mountains and Piedmont; perhaps rare in some areas of the Piedmont. Extremely rare in the Coastal Plain.
HabitatGenerally a wetland thistle, found in wet to damp soil of various types of swamps and swampy openings, wet meadows, marshes, and seepage slopes.
PhenologyFlowering and fruiting August-November.
IdentificationSwamp Thistle is one of our tallest thistles, typically 4-6 feet tall, with numerous purple-pink heads. From all other species it differs in lacking spines on the flower head bracts (at most a tiny one less than 2 mm long). This character must be noted when distinguishing it from C. altissimum and C. discolor. When you squeeze the bracts, you will note its stickiness, a good identification character.
Taxonomic CommentsNone

Other Common Name(s)Marsh Thistle
State RankS2S3 [S3]
Global RankG5
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