National Collection Spotlight: Tiburon Mariposa Lily

Tiburon Mariposa Lily (Calochortus tiburonensis) is a critically imperiled lily species endemic to a single summit on the Tiburon Peninsula in Marin County, CA. This California endemic lily boasts a striking flower, featuring hairy petals colored light yellow with flecks of dark purple and brown. With only one population known to exist, the Tiburon Mariposa Lily is listed as Threatened under the U.S. Endangered Species Act. Primary threats to this species include recreational activities and the spread of non-native plant species, necessitating consistent monitoring and management for mitigation.

Calochortus tiburonensis is secured in the CPC National Collection at the University of California Botanical Garden at Berkeley (UCBG). In 2018, UCBG collected seed from the only known population of this species within the Ring Mountain Preserve on the Tiburon Peninsula. This accession, representing over 130 maternal lines, is held in the UCBG seed bank in orthodox storage.

We encourage you to learn more about conservation actions taken for Tiburon Mariposa Lily on its National Collection Plant Profile and help support critical conservation work with a Plant Sponsorship. In celebration of our 40 years of saving plants from extinction, CPC’s 40th Anniversary Campaign is raising funds to sponsor 40 National Collection species, including Tiburon Mariposa Lily. For every $5K raised per plant species, our Board of Trustees will provide $5K in matching funds to bring the species to the full sponsorship level of $10K–doubling the impact of your gift in support of rare and endangered plants!