For reliable determination, mature fruits and plants with well-developed inflorescences are essential. Immature and depauperate collections may be impossible to name. An additional species, C. hookeri, is known from Ontario and could occur in Michigan. See Mosyakin (1995) for more information.
1. Fruit wingless, mostly 2–3.2 mm long.
1. Fruit ± winged, 2.4–4.2 mm long.
2. Inflorescences linear, rather loosely flowered; larger fruits 2.4–3.1 mm long (excluding apiculus).
2. Inflorescences narrowly clavate to ovate in outline, densely flowered except at the very base; larger fruits 3.2–4.2 mm long (excluding apiculus).
All species found in Corispermum
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. July 17, 2019. https://www.michiganflora.net/genus.aspx?id=Corispermum.