Lactuca serriola L.
Common Name: PRICKLY LETTUCE
Coefficient of Conservatism: *
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Ad B-Forb

A European weed, along roadsides and railroads; in fields, gravel pits, alleys, and disturbed sites; gardens and nurseries; sometimes in moist ground. During the decade 1884–1894, collected in six counties across the southern Lower Peninsula; not in the Upper Peninsula until 1933 and still very local there.

The stiff prickles on the midrib are unique among our species of Lactuca (though some others may have hairy midribs) and will also distinguish this species from any species of Sonchus (e.g., S. asper), which may have prickly margins but smooth midribs. Lactuca biennis may have a few bristles on the midrib beneath.

Locations

Allegan County
Alpena County
Antrim County
Barry County
Bay County
Benzie County
Berrien County
Calhoun County
Cass County
Cheboygan County
Emmet County
Genesee County
Gratiot County
Hillsdale County
Huron County
Ingham County
Isabella County
Jackson County
Kalamazoo County
Kent County
Leelanau County
Lenawee County
Livingston County
Mackinac County
    Only on Bois Blanc, Mackinac, Round Islands
Mecosta County
Menominee County
Midland County
Monroe County
Montcalm County
Montmorency County
Newaygo County
Oakland County
Oceana County
Ogemaw County
Ontonagon County
Osceola County
Oscoda County
Otsego County
Ottawa County
Presque Isle County
Saginaw County
Sanilac 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 12, 2017. http://michiganflora.net/species.aspx?id=389.