My local chapters of the California Native Plant Society are the South Coast Chapter (Palos Verdes Penninsula and San Clemente and Santa Catalina Islands) and the Los Angeles/Santa Monica Mountains Chapter. I wonder if there's major differences between them? One might imagine so, based on their meeting places. The SC-CNPS meets at the South Coast Botanic Gardens mid way up to the top of snooty PV, whereas the LA-CNPS meets in the renter's paradise of Santa Monica. I admit I'm drawn to snooty, in part because it's easier to drive to.
If I ever check them out, expect a full report.