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.