1. Basal leaves at least twice-compound; margins of leaflets minutely ciliate, with ca. 3–5 (–7) coarse and irregular teeth or lobes on a side.
1. Basal leaves simple or trifoliolate; margins of leaflets smooth and glabrous, the principal ones with ca. 10–40 fine and regular teeth on a side.
All species found in Thaspium
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. May 28, 2020. https://www.michiganflora.net/genus.aspx?id=Thaspium.