The San Diego State University Herbarium (SDSU) is a depository of over 26,000 vascular plant specimens, nearly 500 specimens of algae, and a growing collection of bryophytes and lichens. These are all used in research and teaching. 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. The SDSU Herbarium both receives and provides loans of plant specimens used in active systematic research. The herbarium algae collection consists of specimens from the Pacific coast of the United States and Baja California, Mexico and from the Gulf of California, Mexico, with some collections from Hawaii.