Compilation of available herbarium records, as well as additional collections, lead to an estimate of 6,108 identified lichen specimens collected in Iowa that are included in the Iowa Lichens Database. Approximately 35% of the Iowa lichen accessions were collected prior to 1960, while -65% were collected after 1960. These accessions correspond to 448 species reported for Iowa. Of these 448 species, 42 species of macrolichens appear to be rare or extirpated, based on the criterion of no collection records after 1960. Searches for one of these potentially rare or extirpated lichens, Lobaria pulmonaria, have, thus far, been unsuccessful, and the available evidence supports the conclusion that this lichen species is extirpated from Iowa.