Threatened by vehicles, development, grazing, non-native plants, recreational activities, and road maintenance. See Bulletin of the Torrey Botanical Club 51:295 (1924) for original description, and Phytologia 66(4):326-327 (1989) 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
.