Tagetes erecta L. (incl. T. patula L.), Marigold, was collected by Douglass Houghton at Sault Ste. Marie, Chippewa Co., Oct. 1, 1831! – but without any indication of whether planted or wild. It resembles a large Dyssodia, is similarly glandular and strong smelling, and would run to here in the key. Tagetes, however, has much larger heads with longer, more conspicuous rays and involucral bracts connate for at least 1/3 of their length (as opposed to ± free). Though not confirmed as a wild plant in Michigan, T. erecta has been collected as an escape in adjacent Lambton Co., Ontario.
All species found in Dyssodia
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 29, 2017. http://michiganflora.net/genus.aspx?id=Dyssodia.