Portrait (group) International Association of Wood Anatomists (captioned), 1930

There are an estimated 11,000+ photographic images in the collection in the form of positive and negative prints, color slides, and glass slides. The photography documents botanical expeditions and fieldwork, tapping and production operations of latex-bearing trees, identity and forms of plant species (especially those producing gums and rubbers), plant cultivation, and regional surveys of forest and agricultural habitats. Comprehensive regional surveys in Thailand, Puerto Rico, and the Peruvian Amazon include aerial photography. Some of the photographic material consists of line drawings of plant species, diagrams, and maps. Much of the photography is captioned and has been used in published material (Series 10), documenting a variety of research projects and botanical expeditions throughout the tropics. See Series 3: Research Papers for a photo index list.

Photos appear in single shots, numbered photographic sequences, scrapbooks (intact and disassembled), and suspended on hanging mounts ("Fotofolio" books). There are four boxes of color slides, some of which duplicates other photographic material. Images are organized alphabetically by plant species, botanical product, country, or location. Positive and negative prints have been cross-referenced with Dr. Williams' identifying numbers where possible. Major pictorial sequences have been coded systematically as follows: D = Dahomey; E1 = Puerto Rico defoliation study; IC = Indochina; M = Manilkara; PR = Puerto Rico; T = Texas; #-63/64 = Thailand, 1963/64; #-65 = Thailand, 1965; W = Vanilla.

Photographic subjects include surveys of latex-yielding species (e.g. Achras, Castilloa, Cnidoscolus, Couma, Dyera, Hevea, Manilkara, Palaquium, Sapium et al) and latex products (e.g. balata, chicle, chilte, gutta-percha, jelutong, leche-caspi et al). There are photo surveys of the Marshall Field Amazon Expedition (1929); exploration of South America during World War II; comparative studies of the forest resources of Puerto Rico, Texas, and Thailand relating to herbicide testing; and the economic botany of the Caura and Orinoco Valleys, Venezuela. Much of the collection has ethnographic significance as Dr. Williams photographed individuals of aboriginal cultures in the context of their aesthetic, material, economic, and social culture. There are portraits of Dr. Williams, his wife and family, and group photos of professional organizations. Oversize photos are located in Boxes 33 and 34. Photographic material can also be found in Series 2: Manuscripts & Typescripts; Series 3: Research Papers; and Series 4: Personal Papers.

Arranged by media, thereunder by size, thereunder alphabetically by subject.