From Flora of Indiana (1940) by Charles C. Deam

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Indiana Coefficient of Conservatism: C = 7

Wetland Indicator Status: FACU

Diagnostic Traits: perennial to ca. 1 m tall; leaves 2-3 ternate, leaflets coarsely toothed or cleft; nodes distinctly hispidulous; umbel bracts lacking or minute; flowers yellow; fruits oblong, ca. 6 mm long, with prominent winged ribs.

Thaspium chapmanii, compared to T. trifoliatum, is generally taller, with more dissected and more pubescent leaves. The flowers are pale yellow-cream flowers and, most definitively, the fruits are granular-pubescent between the wings. This species is more common in Indiana than T. barbinode.