Rare Plant Research

Saving rare native plants from extinction on Ring Mountain.

UPDATED: MAY 30, 2018

A Unique Ecosystem

With native grasslands and serpentine soils, Ring Mountain is home to a variety of rare and endangered plant species.  Serpentine soil, with high concentrations of heavy metals and low concentrations of essential nutrients, gives rise to plants that adapt to survive here and cannot live in other conditions.

Monitoring and Reintroduction

Research focuses on three plant species:

  • Discovered in 1971, the federally threatened Tiburon mariposa lily (Calochortus tiburonensis) grows here in serpentine soil, and nowhere else.
  • With only two isolated wild populations, Tiburon jewelflower (Streptanthus glandulosus niger) is a serpentine annual on the brink of extinction.
  • Once prolific in the North Bay, showy Indian clover (Trifolium amoenum) was last documented on the serpentine slopes of Ring Mountain in 1961.

Research efforts include:

  • Monitoring Mariposa lilies on the hilltop, to study the plant's ability to enter dormancy for many years in unfavorable climatic conditions.
  • In 2017, researchers transplanted Tiburon jewelflower in two locations on Ring Mountain.
  • In 2018, scientists reintroduced showy Indian clover to see if it can grow and flourish.

Get Involved

Since 2011, the Marin County Open Space District has collaborated with the Nature Conservancy on preserving Ring Mountain. Join a volunteer workday to help remove invasive species, collect seeds, or install native plants. Kids ages 5 and up are welcome with an adult. Check the calendar for Ring Mountain volunteer opportunities.