Seriously threatened by agriculture, urbanization, overgrazing, non-native plants, and trampling. See Bulletin of the Torrey Botanical Club 68:155 (1941) for original description, and American Journal of Botany 69:1082-1095 (1982) 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
.