California has one of the most diverse floras on earth. A wealth
of distinct habitats, varied soils, and microclimates, in
combination with millions of years of semi-isolation by the Pacific
Ocean to the west and the rugged mountains and deserts to the
east, have produced a terrestrial vascular flora estimated to
contain more than 5,000 native species- over one-third of which are found nowhere else on Earth- and 1,000 introduced
species. In addition, nutrient-rich ocean currents along the coast support a diverse marine flora of about 670 species.