The present paper comprises an annotated list of 2,734 collections of Ohio plants, representing some 1,315 different species, varieties, and forms in 699 genera and 236 families. The sequence of families followed is that of the author’s “A preliminary classification of the plant kingdom to families,” which, in turn, is based, with modifications, on the latest available studies of the various groups-the systems of Engler & Diels and of Hutchinson being followed in major part.