The US Department of Agriculture's National Fungus Collections is one of the world's largest mycological institutions, housing over one million species of fungal specimens. Amateur mycologist Maurice Burke Walters's fascinating collection of hand-colored photographs is also held there. Walters's collection reveals the often-solitary practice of foraging, the then-nascent science of mycology, and the USDA's evolving interest in documenting the nation's fungi (over 10,000 named species are found in the US).