Cirsium discolor (Muhl. ex Willd.) Spreng.
Family: Asteraceae
field thistle,  more...
[Carduus discolor (Muhl. ex Willd.) Nutt.,  more]
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Aaron Carlson  
Etymology: discolor = two or different colors.
Plants
: Erect perennial, 3-7 ft tall, silvery, widely branching, spiny.
Leaves
: Large, firm, spiny, deeply pinnately-divided, underside with a whitish fuzz.
Flowers
: Head up to 1 1/2 in wide with pale pink disc flowers, 1 to many heads on a somewhat leafy stalk.
Phenology
: Blooms July to October.
Habitat
: Dry to moderate moisture; prairies and fields.
Conservation Status
: Native.
Very spiny biennials 1-3 m tall, with taproot and spreading fibrous lateral roots. Stem deeply ridged, sub-glabrous to glabrous, much branched. Leaves ovate to lanceolate, 11-40 cm long, all deeply undulate-pinnatifid, the caudate-acuminate primary and secondary lobes tipped by elongate yellow spines, the margins more or less strongly revolute, densely white-woolly beneath, crisped-hispid to subglabrous above. Heads with rather light rose-purple corollas,[rarely white] usually solitary at the end of leafy branches. ln volucre 2-3.5 cm long, the bracts lanceolate with narrow glutinous ridge, acute, the outer abruptly contracted into slightly reflexed or divergent slender spines 3-7 mm long, the inner with erose-scarious tips. Achenes 4-5 mm long.

Johnson, M.E. and H.H. Iltis. 1963. Preliminary reports on the flora of Wisconsin: No. 48. Compositae Family. Wisconsin Academy of Sciences, Arts & Letters. 52:255-342.

Not uncommon in S and SW Wisconsin in sunny habitats, in wet to mesic-dry-prairies, an indicator of mesic prairie (Curtis 1955, 1959), often on railroads, lake shores, in sedge meadows, and occasionally weedy in roadside ditches and well-drained, light soil. Flowering from mid-July to early September; fruiting from early August through September.

This species hybridizes with Cirsium altissimum.

Johnson, M.E. and H.H. Iltis. 1963. Preliminary reports on the flora of Wisconsin: No. 48. Compositae Family. Wisconsin Academy of Sciences, Arts & Letters. 52:255-342.

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Derek Anderson  
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Christopher Noll  
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Steve C. Garske  
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Chris Noll  
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Robert W. Freckmann  
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Robert Bierman  
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Richard Bauer  
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Merel R. Black  
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Steve C. Garske  
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Christopher Noll  
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Derek Anderson  
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Circium discolor  
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Aaron_Carlson  
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Aaron_Carlson  
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Aaron Carlson  
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Aaron_Carlson  
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