Mushrooms must be among the fastest-growing organisms. Take soil. Add rain. Poof! Mushrooms appear overnight. Or seem to. Wikipedia cautions that most varieties actually take several days, and some species grow very slowly.
Mushrooms belong to the fungus group of organisms, along with yeasts and molds. Mushrooms live most of their lives underground in the form of mycelium. Mycelia are thread-like life forms, usually invisible to the naked eye, that form branching networks that may extend to a few inches or to thousands of acres. Mycelia are an important organic component of soils. They help soil decomposition and facilitate entry of water and nutrients into the soil, greatly benefiting plants and other soil-dwelling organisms. They may also play a role in cleansing soil of petrochemicals and other pollutants. When mycelia mate and set fruit, mushrooms result. Mycelia are like an invisible underground apple tree, and mushrooms are its apples.
It should go without saying, but bears repeating anyway, that only a trained mycologist can safely distinguish the harmless from the poisonous varieties. The only safe thing for the rest of us to do is to leave them alone and enjoy the sight of them. Just as quickly as they appear, they’ll fall apart and vanish back onto the soil.
Jutta Burger, a Chavez Park Conservancy board member and trained naturalist, has identified one of these species as probably Volvopluteus. If you are a mycologist, perhaps you could identify the others? Use the comment form below.