Barbara College). He helped develop the botany major in 1947 and taught various courses in botany and ecology until 1976 when he retired from UCSB. He continued in a teaching capacity as adjunct professor of botany at the University of Texas from 1974 to 1992. His studies were executed to observe the factors that control plant distributions under the influence of chemical interaction. He’s made substantial contributions to the field including his more prominent paper on “The Role of Chemical Inhibition in Vegetation Composition” in 1966, which paved the way for the study of allelopathy. The paper highlighted phytotoxic terpenes released by shrubs and their influence on the inhibition of seedling establishment. He highlighted the importance of the influence of these organisms that produce water-soluble toxins, which restrict herb development on ecosystem composition. Muller founded UCSB’s Herbarium in the early 1950s and was Curator from 1956 to 1964. In addition to his teaching duties during his years at UCSB, Muller conducted numerous research studies, funded partly by four National Science Foundation grants, on allelopathic mechanisms in California plant communities and systematics and evolution of the species Quercus. He published over 110 articles and books, peer reviewed numerous articles and proposals, and supervised and worked with over 15 graduate students. He published two monographs: The Central American Species of Quercus and The Oaks of Texas as well as provided treatments for the genus in Arizona Flora, Flora of Panama, Manual of the Vascular Plants of Texas, and Flora North America. Muller also made contributions to the study of oaks in taxonomic classifications. He published papers regarding the anatomy of oak species, their correlation with soil nature factors as well as their dispersals. He was one of the first to acknowledge hybridization of oaks and its effect on the relationship between species. He became leading authority on the genus Quercus. His focus on oaks continued for the rest of his career and led to the naming of new species. Throughout his career, Muller took collecting trips to Costa Rica, Cedros Island off of Baja California, Texas, Southern California, and Mexico, and went twice to Europe in the 1950s to study oak specimens at various herbaria. In the course of his years at UCSB, Muller deposited over 15,000 oak specimens in the UCSB Herbarium, including 90 type specimens. In 1940 he published a new method for excavating root systems called the bisect-wash method.