Cal. Fish & Game Code § 1901

The department shall establish criteria for determining if a species, subspecies, or variety of native plant is endangered or rare. As used in this chapter, “native plant” means a plant growing in a wild uncultivated state which is normally found native to the plantlife of this state. A species, subspecies, or variety is endangered when its prospects of survival and reproduction are in immediate jeopardy from one or more cause. A species, subspecies, or variety is rare when, although not presently threatened with extinction, it is in such small numbers throughout its range that it may become endangered if its present environment worsens.