Cirsium muticum Michx.
Common Name: SWAMP THISTLE
Coefficient of Conservatism: 6
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt B-Forb

Calcareous shores, sedge meadows, fens; swamps of cedar, tamarack, and other conifers (less often hardwoods); moist ground along rivers and streams.

The flowers are a deep rose-purple; combined with the relatively unarmed stem, they make this species unusually attractive as thistles go. White-flowered plants [f. lactiflorum Fernald] have been collected in Keweenaw, Livingston, and Oakland Cos. The phyllaries are less acute (even obtuse or blunt) compared with our other small-headed thistles (C. arvense and C. palustre, both introduced, weedy species), which have pale pink-purple flowers. Occasionally the leaves are lightly tomentose beneath, but not enough so to hide completely the green surface of the blade.

Locations

Alcona County
Alpena County
Antrim County
Arenac County
Baraga County
Barry County
Bay County
Benzie County
Berrien County
Calhoun County
Cass County
Charlevoix County
Cheboygan County
Chippewa County
    Including Drummond Island
Clare County
Clinton County
Crawford County
Delta County
Dickinson County
Emmet County
Gogebic County
Grand Traverse County
Gratiot County
Hillsdale County
Houghton County
Huron County
Ingham County
Iosco County
Iron County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lake County
Lapeer County
Leelanau County
Lenawee County
Livingston County
Luce County
Mackinac County
Macomb County
Marquette County
Mason County
Mecosta County
Midland County
Missaukee County
Monroe County
Montcalm County
Montmorency County
Muskegon County
Newaygo County
Oakland County
Ogemaw County
Ontonagon County
Oscoda County
Ottawa County
Presque Isle County
Roscommon County
Schoolcraft County
St. Clair County
St. Joseph County
Tuscola County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 13, 2017. http://michiganflora.net/species.aspx?id=288.