Series I holds materials written by Nehrling either in his own handwriting or published in newspapers. The series begins with several individual files; outgoing correspondence includes lists of letters written as well as typewritten and handwritten letters on a variety of subjects. Letters written to A. H. Andrews may have been published in the American Eagle. One book review is only in note form. News clippings show the places where Nehrling published his writing apart from the American Eagle. He prepared outlines for books that do not seem to have been published. Some of the incomplete writing may relate to these plans for more publications. Nehrling used published materials for information about plants and these are all marked with their sources. The first sub series consists of articles written for the American Eagle, beginning with printed copies of the newspaper that continue until 1970 because Nehrling's articles were so popular that they continued to be reprinted long after his death. Nehrling's partial index of his American Eagle articles precedes his manuscripts of the articles arranged chronologically. The second sub series holds manuscripts for which no publication information exists arranged alphabetically. These manuscripts are all written in his own hand apart from The Amaryllis which is typewritten. The final sub series contains incomplete writings arranged alphabetically with a folder containing a few sheets whose topic could not be identified. Writings with the same title but held in separate sub series are similar, but they are not exact duplicates.
