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Plants of fields, roadsides, open disturbed areas; flowering July to August.  Not native.  Our plants are subsp. acanthoides (the only subspecies represented in North America)..

Annual or biennial.  Stems and branches are provided with conspicuous, spiny-winged tissue.  Typical height is 2 to 4+ feet.

Overall inflorescences are open, sometimes many branched.  Branches are usually sharply ascending, spiny-winged.  Branch inflorescences consist of from 1 to a few flower heads, mostly clustered at tips of branches or in upper leaf axils.

Flower heads are discoid; ray florets are lacking.  Disc florets are narrowly tubular, bisexual and fertile; corollas are purple/magenta.  Involucres are 14-20 mm highInvolucral bracts are spreading to ascending and spine tipped.  Peduncles are spiny-winged; leafy.

Basal leaves are usually deciduous by flowering (unless plant was previously mowed).  Stem leaves are narrowly lanceolate or oblanceolate in overall outline, deeply lobed, spiny-margined.

Cypselae are obovoid, straw-colored to tan, striped.  The pappus is of minutely-barbed, unbranched (i.e., not feather-like) bristles, fused at the base and detaching together.

A very spiny plant!

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Similar species:  plants in the genus Cirsium (thistles).
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