Floristic data, keys to identification, and dot distribution maps are presented for Thaspium barbinode, T. trifoliatum, Zizia aptera, and Z. aurea. Two varieties are accepted within T. trifoliatum: var. trifoliatum known from only two collections in the state, and var. flavum which is common. Thaspium pinnatifidum, long attributed to Ohio, is excluded from the known flora; all specimens so determined proved to be misidentified forms of T. barbinode.