Last month, after the first major storm of the season, I decided to risk the mud and go for a run on one of my favorite trails in Tilden Park. The trails, soft and spongy a week before, had turned into a gloppy, goopy mess, more suited to glissades than sprints. As I struggled to maintain momentum without falling, I couldn’t help but notice that the rains had brought more than mud.
All along the trail, mushrooms peeked out through the carpet of pine needles and sodden leaves. Before I knew it, Eric Burdon was singing in my head, “There was long ones, tall ones, short ones, brown ones, black ones, round ones, big ones….”
Some stood alone, as big as portabellas, others barely the size of a dime, huddled together in little bunches, still more clung to tree trunks and rotting logs. Mushroom season had sprung.
And I was singing along with Eric.
Not everyone shares my fascination with mushrooms, as famed fungi fanatic David Arora makes clear in his classic field guide, Mushrooms Demystified. Arora does his best to dispel what he sees as widespread “fungophobia” among Americans, a fear he calls irrational, given that only five or six of several thousand different wild North American mushroom species are deadly. Of course, the trick is knowing which ones.
Every year, hundreds of people get seriously ill from eating foraged wild mushrooms, prompting state Public Health Director Ron Chapman to issue an annual warning after winter’s first heavy rains to resist the urge to do so. Just last month, four people died at a home for the elderly in Placer County after their caregiver inadvertently served them what authorities believe were death caps.
Perhaps not surprisingly, most reports to the California Poison Control System involve children who sampled mushrooms that popped up in their lawn or neighborhood park. Since last January, 903 kids under six have required treatment for ingesting mushrooms.
Even experienced mushroom hunters can mistake poisonous and edible varieties, especially if they learned to forage in another country. Kent Olson, medical director of the CPCS, warns on the agency’s web site that many poisonous mushrooms in Northern California bear a striking similarity to edibles that grow in Europe and Asia, confusing even the most experienced mushroom foragers.
If you get the urge to test your mushroom hunting skills, do yourself a favor. Get a field guide like Arora’s and study it carefully to learn distinguishing characteristics of some of our resident species, both deadly and safe. And then sign up for a day hike or camping foray with the Mycological Society of San Francisco so you can forage with the experts.
But there’s far more to appreciate about mushrooms than their culinary appeal. Scientists are just beginning to get a handle on just how diverse the fungal kingdom really is.
For most of modern scientific history, fungi were misclassified as plants, based on their soil-bound, stationary existence. Had we just the naked eye to rely on, we might still restrict the world of fungi to the transient spore-filled fruiting bodies that burst through the soil long enough to reproduce. That would be like thinking the New York City subway system begins and ends with the above-ground stations scattered around the city streets.
But thanks to advances in microscopy and biochemical analysis techniques, scientists discovered that these “macrofungi” account for just a fraction of the diversity of species found in the fungal kingdom, which includes molds, yeast, lichens (a composite of fungi and algae) and parasitic rusts and smuts. (Corn smut, despite its unappetizing name, is in fact a tasty delicacy, better known by its Mexican name, huitlacoche.)
Even the reproductive structures we call mushrooms represent just the tip of the fungal iceberg, which consists of an intricate network of filaments (called mycelium) and lives as part of a thriving community of microbial and fungal species at different depths in the soil.
Fungi play critical ecological roles as the primary decomposers in woodland and forest ecosystems and degrade everything from leaf litter to the notoriously indestructible lignin, which gives woody plants and trees strength and durability. Earlier this year, researchers discovered fungal species that can even break down polyurethane plastic.
Another type of fungus lives among the roots of plants and trees in a mutually beneficial symbiotic relationship. California’s iconic oaks depend on these mycorrhizal fungi to extend the reach of their roots to scavenge water and nutrients and to recycle nutrients from their own shed leaves. In exchange, fungi get carbohydrates from the trees.
In a 2001 paper describing the diverse functions of these symbiotic “ectomycorrhizal” partnerships, mycologist Anders Dalhberg ventured that perhaps 6,000 fungal species form these alliances with plants, allowing that the estimate must be conservative since some known species don’t produce fruiting bodies and it’s not clear how many remain unknown.
Though there is no such thing as a definitive field guide to mushrooms—there are simply too many mushroom species and too few mycologists to classify and identify them—Arora’s Mushrooms Demystified comes darn close. I’ve used it time and again to identify specimens throughout California, including a beautiful fly agaric in my own front yard.
On my run, I found what I thought was a Russula sanguinea, easy to recognize for its bright red cap and stem separated by white gills. I also saw what looked like a destroying angel, Amanita ocreata, on the trail. I brought them home, pulled out Arora’s guide and confirmed the Russula without a doubt. And I’m pretty sure I was right about the destroying angel.
I love exploring the woods to test my mushroom knowledge and look for new species I’ve yet to identify. But I’m still a dilettante. For now, I’m content to celebrate the ecological wonders and diversity of fungi with a long-haired leaping gnome in my head. And buy my wild mushrooms at the store.