Series I is divided into thirteen subseries by the various aspects of Mulford and Racine Foster's work. Correspondence is the first subseries and is arranged alphabetically either by author or subject. The letters cover both personal and business subjects. Publications by both Mulford and Racine Foster form the second subseries. The subseries begins with articles and news clippings mostly about Mulford Foster or with references to plants named by or for him followed by lists of some of his publications. The publications are then arranged in alphabetical order by title. Correspondence with publishers forms the next subseries and includes correspondence with anyone connected with the process of publishing including advice on spelling from the Brazilian Embassy. Materials are arranged alphabetically by the title of the publication or the author except for one folder of chronological correspondence. Plant Collecting holds collecting notebooks, botanical drawings, photographs and other materials relating to Foster's collecting trips arranged alphabetically by destination. Materials not related to a specific trip begin the subseries and are arranged in alphabetical order. Art contains drawings, photographs, programs and news clippings documenting Mulford Foster's own art and his interest in others' work arranged in alphabetical order. Nursery Business was selected as a suitable heading to describe the aspect of Mulford and Racine Foster's work that included growing, hybridizing and selling plants. Folders are arranged in alphabetical order. Mulford Foster described himself as a landscape architect so the Landscape Architecture subseries represents an important part of his work. Arranged alphabetically, this subseries includes information on such projects as Floating Islands in Leesburg, which was not completed and Marineland near St. Augustine. Before moving to Florida, Mulford Foster worked for the Davey Tree Company in Virginia and a small amount of materials relating to that period is held in a single folder. Similarly, Racine Foster operated a tea room at the Magnolia Avenue property and a small subseries provides information concerning the Latchstring Tea Room and other businesses on the property, such as, the Tropical Arts Studio. Both Mulford and Racine Foster were involved with bromeliad societies and the next subseries documents their interest. Arranged alphabetically, correspondence, newsletters and photographs show the activities of the societies. Rosettes celebrating the first Bromeliad Society Show dedicated to Mulford B. Foster in 1964 may be found under Florida West Coast. The Lectures subseries provides information about Mulford Foster's lectures including notes and a slide list For correspondence concerning arrangements for the lectures, please see the the Correspondence subseries. Plant Information holds research files and photographs arranged in alphabetical order. Foster collected material on an variety of plants though information about bromeliads predominates. Finally, the Personal Information subseries holds personal materials concerning Mulford and Racine Foster and their families and materials that were not readily accommodated in any other subseries. Legal documents, memorabilia, diaries, certificates, news clippings, photographs, biographical information and other similar materials may be found here arranged alphabetically.