Muir is credited with helping to create the National Park System, as well as preserving natural treasures like redwood forests and the California coast.
But he was also an accomplished botanist, collecting and cataloging countless plants during the late 1800s and early 1900s. His collection ranged from miniscule fern spores to flower petals, according to the CoCo Times.
Muir once wrote about how he wept upon discovering a rare orchid in a swamp.
His collection was unusually far-flung. Muir was known for pressing flowers in books, and then mailing them around the globe.
A photographer and historian spent five years investigating Muir's collection, tracking down specimens in museums and other collections. They then used high-powered imaging equipment to produce giant blown-up photos of the plants.
Many of the images needed to be digitally restored to reflect what their condition might have been 100 years ago.