The Clark Herbarium (founded in 1949) serves as a reference library to the plant diversity and changes of Southern California. With almost 10,000 specimens, the Clark Herbarium includes dry botanical mounts, most of which were collected from the Riverside region and surrounding counties by J. C. Roos and other botanists between 1920 and 1990. A small collection of lichens and fungi was assembled during the 1930s by Edmund C. Jaeger, and was later donated to the Museum during his tenure as Curator of Plants. All these materials now represent an important database describing the distribution of native plant species in the southwestern U.S., which is now a vastly altered environmental setting. James Bryant, former curator, retired.