PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES FOURTH SERIES G Dallas Hanna Anniversary Volume Vol. XXXII, No. 20, pp. 587-677; 14 figs., 5 pis. November 29, 1968 A FLORA OF THE SAN BRUNO MOUNTAINS SAN MATEO COUNTY, CALIFORNIA By Elizabeth McClintock California Academy of Sciences San Francisco, California and Walter Knight Regional Parks Botanic Garden Berkeley, California In collaboration with Neil Fahy Standard Oil Company San Francisco, California INTRODUCTION The San Bruno Mountains in northern San Mateo County and the hills in San Francisco County, California, constitute the northern outliers of the Santa Cruz Mountains. The San Bruno Mountains have remained relatively undis-turbed, except for the City of Brisbane and today constitute an "island" entirely surrounded by metropolitan areas. The covering of vegetation on the San Bruno Mountains contains many of the plants which once were found to the north in San Francisco where only fragmentary remnants of the natural vegetation re-main. However, the pressure of metropolitan development is moving toward the San Bruno Mountains and soon some of their sections will undergo changes. This flora records the plants to be found there before these changes occur.