Cirsium palustre (L.) Scop.
Common Name: MARSH THISTLE, EUROPEAN SWAMP THISTLE
Coefficient of Conservatism: *
Coefficient of Wetness: -3
Wetness Index: FACW
Physiognomy: Ad B-Forb

A native of western Europe, collected in New Hampshire and Newfoundland early in the 20th century and becoming locally abundant as it spread. First collected in Marquette Co. in 1934 by M. L. Fernald, who thought it likely to be native but admitted that its behavior in the state “should be watched.” Unfortunately, we have watched it spread throughout the Upper Peninsula, to islands in the Straits of Mackinac, and by 1959 to the mainland of the northern Lower Peninsula. It continues to move south. Tall plants form dense ungainly colonies along roadside ditches and adjacent swamps, whence it spreads to shores and remoter wetlands. The tragic spread of this pest into natural wetlands is doubtless aided by logging roads and other disturbance.

Locations

Alger County
Baraga County
Charlevoix County
    Only on Beaver Island
Cheboygan County
Chippewa County
    Including Drummond Island
Delta County
Dickinson County
Emmet County
Gogebic County
Iron County
Kalkaska County
Keweenaw County
Leelanau County
    Only on Fox Islands
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Marquette County
Mason County
Menominee County
Ontonagon County
Schoolcraft County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 13, 2017. http://www.michiganflora.net/species.aspx?id=289.