Polanisia dodecandra (L.) DC.
Common Name: CLAMMY-WEED
Coefficient of Conservatism: 5
Coefficient of Wetness: 5
Wetness Index: UPL
Physiognomy: Nt A-Forb

Sandy shores of the Great Lakes and nearby disturbed sites; roadsides, railroads, gravelly bluffs, especially inland.

Often called P. graveolens Raf. Variety dodecandra is considered native in our area and elsewhere in eastern North America, and has petals that do not exceed 8 mm in length (usually ca. 4–6 mm). In var. trachysperma (Torr. & A. Gray) Iltis, sometimes treated as a distinct species, the petals are longer, ca. 10–12 (–15) mm in our material; this sometimes cultivated showier western North American variety is adventive or escaped into disturbed areas locally in southern Michigan (records from Jackson, Kalamazoo, Kent, Mecosta, Ottawa, and Wayne Cos.) In both varieties, the leaves, stems, and fruit are ± densely glandular-pubescent, and the clammy plant has a rank odor.


Bay County
Benzie County
Berrien County
Cass County
Charlevoix County
Crawford County
Dickinson County
Ingham County
Jackson County
Kalamazoo County
Kent County
Lake County
Lenawee County
Livingston County
Manistee County
Mason County
Mecosta County
Monroe County
Muskegon County
Newaygo County
Ottawa County
Washtenaw County
Wayne County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 7, 2021. https://michiganflora.net/species.aspx?id=821.