The combined Herbarium of Rancho Santa Ana Botanic Garden and Pomona College ("RSA-POM") is about the tenth largest in the U.S. and the third largest in the western U.S., with current holdings totaling over 1,100,000 specimens.

Library and Archives

Acquisitions at the RSABG research library increase yearly and include bound journals and periodicals.The library also houses the Archives which include the Marcus Jones Archives and Collection, as well as the Samuel Parish Collection; both men were local botanists in the late 19th century.

Living Collection

The Living Collection contributes to the research and conservation mission of the Garden. Through public horticulture, the Living Collection also promotes the thoughtful utilization of our natural heritage. The Living Collection covers 86 acres housing over 2,000 accessions of plants native to California and Baja. Those accessions represent 1,200 taxa, different kinds of plants, including 750 species.

Seed Conservation Program

The primary function of RSABG's Seed Program is the curation and management of the Garden's extensive seed collection. The collection is comprised of over 4,900 accessions representing over 2,100 California native plant species and cultivars.