- The Endemic flora of the State of California — native plants found within its borders, and nowhere else in nature.
- The largest area of the state is in the Mediterranean climate floristic region, within the California Floristic Province — with the greatest number of endemic plants in North America.
- The state's other floristic regions include: the low deserts within the Sonoran Desert Floristic Province; the high deserts and eastern borders' dry steppes areas within the Great Basin Floristic Province; and the moist northern border section within the Rocky Mountain Floristic Province.