Threatened by development. Seriously attacked by the five-spined ips bark beetle at Torrey Pines SR, but biological control apparently has contained this infestation. See American Forests 91(10):26-29 (1985) for species account, and Systematic Botany 11(1):39-50 (1986) 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
.