This curious shrub is found in the chaparral zone. Maybe I just haven't tramped about as much in chaparral as I think I have, but this plant is unusual to my eyes because I simply had only seen it once before (not in bloom), and that was in a moist, shaded woods, not a chaparral habitat.

If you want to look for Styrax, it blooms toward the end of April. You can find some in the area near Rescue; here is a map.

In the 1750s, Linnaeus described plant species that were known to him from the wild and then cultivated in western Europe, during a time when California native plants had not yet been collected for scientific or horticultural use. But a species native to southern Europe turned out to be also a native shrub of Southern California, Styrax officinalis L. var. redivivus (Torrey) H. Howard (Family Styracaceae). Indeed, styrax was the Greek name given to that plant by Theophrastus, the Father of Medicine, because the Mediterranean form of this species provided gum storax from the bark. Our homegrown variety redivivus is known as snowdrop bush or California storax. source