An Amateur Botanist Finds the Rare Geothallus Tuberosus

California is one of the most geologically and biologically diverse places on Earth. Even as climate and development pressures grow, it’s still possible to find incredible native plants right where you live! Take Geothallus tuberosus, for example.

What is Geothallus tuberosus? It’s the botanical name for a plant called Campbell’s liverwort—a member of a species of ancient plants that have existed for millions of years. Campbell’s liverwort is extremely rare (CA Rare Plant Rank 1B.1). It is endemic to (which means only found in) California and known only from occurrences in San Diego and Riverside counties. Liverworts don’t have a way to move water and nutrients around their bodies. They absorb water and minerals through their leaves. Instead of roots, liverworts have “root-like” structures that hold them in place. However, they are particularly vulnerable to any soil disturbance and are small enough not to be noticed by someone who might step on them.

Filmmaker Diego Lynch created this video featuring 19-year-old James Davis, a gifted amateur botanist who lives in South Park, San Diego. In his own neighborhood, James discovered that native plants still thrive in the 32nd Street Canyon, including Geothallus tuberosus. James has lived in the area his whole life, which spurred his curiosity about these plants. He interned in the City of San Diego’s Open Space Division—the section of the Parks & Recreation department which oversees San Diego’s undeveloped land and is currently a student at San Diego City College. Special thanks to James and to Diego Lynch for sharing this beautiful video and reminding each of us why the first step to protecting native plants is getting to know the plants that surround us.

Take It Further

  • Why was James surprised to find liverworts in the canyon?
  • Have you seen biological soil crust before? Why is it important not to disturb it?
  • In the video, you’ll notice that James has to get really close to the plants he’s looking at. What do you notice if you look at the small plants growing on the ground in your neighborhood? Try using a magnifying glass to notice the details.


  1. It’s a bit of a challenge to grow to love and embrace a plant named “Liverworts”, but Diego and James video convinced me to start to look for the species in my canyon. If I find some Liverworts I’ll try hard to cherish the little plant in spite of its ugly name. Thanks !

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