Known from fewer than twenty occurrences. Threatened by urbanization and non-native plants. Possibly threatened by erosion. See University of California Publications in Botany 2:239 (1907) for original description and 20:241-392 (1955) for taxonomic treatment.
California Native Plant Society (CNPS).
Inventory of Rare and Endangered Plants (online edition, v8-01a).
California Native Plant Society. Sacramento, CA. Accessed on
.