A botanical survey of the vascular flora of the "planning and zoning jurisdiction" of the city of Ames, Iowa (i.e., the area within a boundary 3.2 km beyond the current city limits) was compiled from 1990 to 2000. During this survey, 916 taxa (71% native) were encountered within this boundary. literature reviews and a survey of Iowa State University's Ada Hayden Herbarium for specimens that had been collected in Ames since 1859 add 204 taxa to the flora. This total of 1,120 taxa exceeds the number of taxa known from any comparable area (including counties) in Iowa. We produced a checklist including date of first record, origin, abundance and habitat codes for all species that were noted during the current survey. Information for historic records includes source and, if based on a herbarium voucher, dates of first and most recent collections. This study reports 58 taxa that are not included in Eilers and Roosa's (1994) checklist of the Iowa vascular flora; 28 species currently or historically known from Ames are included in the 1994 Iowa Department of Natural Resources list of endangered, threatened or special concern species. Two species on the federal list of threatened plant species, LeJpedeza leptoJtachya (native) and Boltonia decu"em (naturalized), are also found within the study area. An outline of previous studies of the Ames flora is presented. Sites containing notable plant assemblages in the survey area are mapped and described. The results of the survey provide both an enhanced general knowledge of the state's flora and an example of local analysis of floristic change. These results are also relevant to conservation efforts, such as habitat restoration and reconstruction, and in evaluating the conservation status of the vascular plant species in the state. This inventory highlights the need for similar, intensive studies of the flora elsewhere in Iowa. The compilation of the historical data for such studies could be greatly aided by the development of computerized catalogs of the state's herbaria.