The San Diego State University Herbarium (SDSU) is a depository of over 25,700 pressed and mounted specimens of vascular plants and over 400 specimens of algae, used in research and teaching. We have initiated a lichen collection, which we plan to add to in the coming years. The purpose of these specimens is: 1) to serve as voucher documentation for research projects; 2) to serve as resources for plant identification; and 3) to serve as exemplars in plant courses. In addition, the herbarium both receives and provides loans of plant specimens used in active systematic research. The herbarium collection specializes in land plant specimens from San Diego County, California, and Baja California, with some collections from Australia, Chile, and the south Pacific.