Herman Silas Pepoon (1860-1941) was a local naturalist with a particular focus on the plants of Illinois and the Midwest. He spent a considerable amount of time exploring Apple River Canyon, where he identified and collected over 500 species of plants. One of his most noteworthy discoveries in the canyon was Bird’s Eye Primrose (Primula mistassinica), a plant previously found only in more northerly locations. Pepoon devoted substantial effort toward the preservation of the Apple River Canyon region, including testifying before the Illinois State Academy of Sciences in 1908 in favor of making it a state park.