Coefficient of Conservatism:
Coefficient of Wetness:
The native range extends barely to southeastern Michigan, where the species was collected in open forests in the vicinity of Trenton and Grosse Isle (both Wayne Co.) as early as 1838 but no more recently than 1917. The only extant native occurrences are on the steep, forested bluffs of the Grand River in Ionia Co. It has also been collected in disturbed ground as an escape from cultivation at East Lansing (Ingham Co.) in 1938 and Bay City (Bay Co.) in 1939. An early (1885) Farwell collection from Copper Harbor (Keweenaw Co.) is not mapped; it may have been cultivated or even simply mis-labelled as it bears a suspicious "½" number.
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 12, 2017. http://www.michiganflora.net/species.aspx?id=787.