Scientists and nature enthusiasts recently explored forests in Napa County, California, hoping to find a rare yellow mushroom called the Manzanita butter clump. The mushroom is extremely uncommon and has been seen only along parts of North America’s western coast. The search highlights growing interest in fungi and the importance of studying the many unknown fungal species on Earth. During the trip, researchers instead discovered many types of lichens on rocks and trees. These organisms, created by partnerships between fungi and algae, show how diverse fungi can be even in a small area of forest.

Scientists say fungi are essential to life on Earth. They help forests recycle nutrients and support many plants and animals. Experts estimate that about 2.5 million fungal species may exist worldwide, but scientists have managed to document only a small portion of them. Much of fungal life grows underground as a huge network called mycelium, which makes fungi difficult to study. Climate change, pollution, habitat loss, and overharvesting are major threats to many fungal species. Because of these risks, scientists and volunteers increasingly work together to observe and record fungi in nature.