PlantWorld: Calochortus Parade, part 3

Serpentine is the 'common name' for serpentinite, a shiny, smooth, mostly green metamorphic rock that is present in fairly large quantities throughout California. It is produced at the margins of the continental crust, particularly on ocean floors, through a complex process involving seawater reacting with mafic and ultramafic rocks to form serpentinite. It is the state rock of California.

Soils derived from serpentine rock are high in several metals, particularly magnesium, and low in most plant nutrients. This prevents most plants from growing in serpentine soils, except those that have evolved a special ability to tolerate these unusual conditions. These plants are called serpentine endemics. There are also plants that are tolerant of serpentine but that can also grow in regular soils.

Calochortus are one of the groups of plants with a high number of serpentine endemic and tolerant species. Perhaps the most famous is Calochortus tiburonensis, a species only discovered in the early 1970s growing in serpentine outcrops on Ring Mountain, in southern Marin county, at the base of the Tiburon peninsula.

The third installment of the Calochortus Parade will focus on the Cat's Ears floral style, of which C. tiburonensis is a member.