Mt. Tamalpais, 2571 feet in elevation, is found eighteen miles north of San Francisco in southern Marin County (see Plate 1). Despite its close proximity to a world port and metropolis, its slopes still display a wildness and natural beauty that have remained relatively unaltered as compared with other areas of the Bay Region and demonstrates ready accessibility to detailed ecological study. The study began during the spring of 1963 when plant specimens were first collected. After a period of reconnaissance and mapping of the vegetation, quantitative samples were taken in the study area in hopes that relationships could be established between plant communities and environmental factors.