The exact year in which the UCLA herbarium was first established is unclear, but it may date back to the period when UCLA was a 2-year, branch campus of UC Berkeley on Vermont Ave in downtown Los Angeles (1919–1929). The core of the herbarium was established through the acquisition of the herbarium of the defunct California Botanical Garden (CBG; 1928-1935). The CBG had reportedly amassed a large herbarium which were transferred to the UCLA herbarium after UCLA started offering classes at its new Westwood campus in 1929. This CBG herbarium included specimens from the Bonati and Tapp Herbaria that were purchased by Elmer Merrill, as well as Merrill’s own personal collections from the Philippines. Merrill was Director of the California Botanical Garden while on leave from UC Berkeley where he was Dean of Agriculture and Director of the Agricultural Experiment Station shortly before it went bankrupt in ca. 1930, and about the same time the herbarium collections were given to UCLA. Merrill went on to Columbia University (Director in Chief of the botanical garden and Professor of Botany), New York Botanical Garden, and Arnold Arboretum (1936—1946 and emeritus until 1956).
Dailey Bruin form October 3, 1957, announcing the construction of the Botany Building.