Threatened by vehicles and road maintenance. Some plants from ALA, LAK, NAP, and STA cos. were previously treated as H. serpentinum ined.; plants from the inner north coast ranges of LAK and NAP cos. are now treated as H. sharsmithiae. Plants from ALA Co. are possibly H. clevelandii; needs further study. Similar to H. sharsmithiae. See University of California Publications in Botany 32:298 (1961) for original description.