Sonchus oleraceus L.
Common Name: COMMON SOW-THISTLE
Coefficient of Conservatism: *
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Ad A-Forb

Sonchus oleraceus A. A. Reznicek

A persistent weed of yards and gardens, cultivated fields, city streets, parking areas, hedges, foundations of buildings, railroad yards, bulldozed land, and disturbed places generally. Michigan records go back at least to 1877, with a fragmentary specimen probably this species from 1846 (Macomb Co.).

Specimens of this species with the largest involucres and those of S. arvensis with the smallest involucres are sometimes hard to assign, especially if underground parts and ligule shade are not observed or recorded on the label. The often large and ± acute auricles on the leaves of S. oleraceus may help; in S. arvensis the auricles run smaller and are rounded (and are also usually smaller and less prickly than in well developed S. asper).

Locations

Berrien County
Cass County
Cheboygan County
Emmet County
Gogebic County
Gratiot County
Houghton County
Ingham County
Isabella County
Jackson County
Kalamazoo County
Kent County
Lenawee County
Macomb County
Marquette County
Mecosta County
Menominee County
Montcalm County
Newaygo County
Oakland County
Osceola County
Otsego County
Schoolcraft County
Shiawassee County
St. Clair County
Van Buren 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=475.