By Paul Belz
Lake Merritt shares many of its treasures in autumn and winter. Birders know these are the seasons when canvasbacks, grebes, buffleheads, and other migratory birds appear in hoards. Observant guests will also find that these are the seasons for the weirdly beautiful organisms we call wild fungi.
Damon Tighe led a group of about fifty curious fungus seekers on a Lake Merritt exploratory hike on December 7. An experienced amateur mycologist, Damon mentioned that he became interested in wild mushrooms after a Sierra backpacking trip where he did not bring enough food. “Besides, they’re like winter flowers,” he said. “They’ll start popping up everywhere after the rain.”
The mycelium, the main part of all fungi, resembles a tangled spider web. It can spread for acres under the soil and live for many years. When conditions are right, the mycelium produces mushrooms or other fruiting bodies. “The mycelium is like the apple tree, and the mushrooms are like apples,” Damon said. The similarity ends here. Plants reproduce through complex seeds; fungi rely on single celled spores, which are scattered by wind, squirrels, banana slugs and other animals that feast on mushrooms.
Another difference with plants is that fungi have no chlorophyll, so they aren’t able to make their own food through photosynthesis- they have to get their energy from an external source. The mycelium of parasitic fungi live inside plants and take some of their energy, saprophytic fungi break down dead organisms to absorb nutrients, and mycorrhizal mycelium attaches to the roots of plants were it helps absorb water and nutrients from the soil while receiving sugars from the plant in return.
We quickly found a pleated inky cap (Parasola plicatilis), a dark colored mushroom that digests itself after its first day of life. This strategy helps it scatter spores “You can eat these, but you can’t drink alcohol for three days afterwards- they inhibit your ability to break down alcohol,” said Damon.
“Eating mushrooms that grow in the city isn’t a good idea. There are lots of heavy metals in the soil,” Damon said. He recommended that foragers search for mushrooms higher in the hills; water that flows downhill hasn’t deposited as many chemicals there.
We found several species that foragers can find in other areas. Honey mushrooms (Armillaria mellea) grew in a cluster from a dead stump. Damon told us that these mushrooms have good tasting caps, and enthusiasts can pull the stalks apart and eat them like string cheese. The prince mushroom (Agaricus augustus) is a large gilled mushroom that has a golden, flat-topped cap when it emerges. “It looks like a marshmallow and smells like almond extract,” Damon laughed.
Foragers need to be able to identify to identify toxic fungi. Many mushroom hunters have mistaken the death cap (Amanita phalloides) for puffballs or edible species from other countries. Damon also pointed out members of the “Lose Your Lunch Bunch”, which cause nausea and other digestive problems, but not death. The yellow stainer (Agaricus xanthodermus) has a cap that turns yellow in places where you stroke it. “I’d never recommend eating a mushroom that stains yellow,” Damon said. This mushroom also has a distinct chemical smell- “It smells like public washroom soap!” one hiker grimaced.
A jack-o’-lantern mushroom (Omphalotus olivascens), another fungus you don’t want to eat, grew from a dead stump. The gills of these big, orange mushrooms bioluminesce, a strategy they may use to attract spore-scattering flies.
Other mushrooms use strong smells as signals to insects. This year’s dry conditions prevented us from finding lattice stinkhorns (Clathrus ruber); Damon hoped they would appear after steady rain. “They smell like dead bodies,” Damon told us. Large openings in their light bulb shaped forms let flies enter to eat the fungus and gather its spores.
Damon was pleased to show us an earth star (Geastrum saccatum). Triangular, pointed structures lift the wrinkled brown center from the soil and expose them to breezes. Wind strikes the little puffballs and causes it to release spores in groups like puffs of smoke.
“Amateurs have made some of the most important discoveries about fungi in the past few years,” Damon said as the walk came to its end. He recommended David Arora’s All the Rain Promises and More as an excellent field guide, and Arora’s Mushrooms Demystified as a more complex and detailed book. Keep your eyes open for wild fungi – you may find something new!