The Chapter's logo is the Tiburon Mariposa (Calochortus tiburonensis)
This extremely rare lily can be seen blooming from the end of May through mid-June among the serpentine rocks of Ring Mountain in Marin County. In fact, this is the only place in the world it has ever been found growing in the wild. The plant was first noticed by botanists in 1971 when the small patch of land on which it lives passed from private into public hands.
Calochortus tiburonensis is now in cultivation and can be seen in botanic gardens.