Distribution of Pteridophytes in Iowa

In 1954 and the early part of this year, in connection with a general study of the pteridophytes of Iowa (1955), the writer made dot distribution maps of the species. The maps were based upon specimens from the herbaria of Iowa State College, Iowa State Teachers College, Grinnell College and the State University of Iowa. The nomenclature and the treatment of the species followed generally that of the New Britton and Brown Illustrated Flora (Gleason, 1952)