Mushrooms in Redwood Regional Park

By Paul Belz

Imagine a redwood forest that is home to strange little life-forms of all shapes and colors. “Mushrooms are interesting to me… because they’re like the flowers of winter. They appear when not a lot of other things are happening in California’s coastal forests,” East Bay Regional Parks naturalist Trent Pearce told a large group at Redwood Regional Park. “Why are mushrooms interesting to you?”

“They look like crazy aliens,” one hiker said.

“They have a hidden side and an emergent side.”

 “They’re not plants or animals.”

 “They sometimes grow in perfect circles.”

Fungi are a separate kingdom of life from plants, animals, and bacteria. The surreal organisms we call ‘mushrooms’ are the fruiting bodies of mycelium, filamentous strands that look like spider webs. Spores, which all fungi use as reproductive cells, develop within the gills or other structures of the fruiting body until wind or animals scatter them. A lucky spore might land in a spot where it can produce its own mycelium, which grows until it touches a compatible mycelium web. The two organisms will share genetic material, and produce new fruiting bodies that will continue the cycle.

Amanita phalloides. Photo: Trent Pearce

Death cap (Amanita phalloides). Photo: Trent Pearce

Trent grinned and showed the crowd a beautiful specimen that is California’s deadliest mushroom, the death cap (Amanita phalloides). When you’re first learning to identify mushrooms, it’s a good idea to start with the most deadly ones so you know what to never eat! This handsome amanita has a large, shiny greenish cap, with white gills on its underside, a ring of tissue around the middle of its stalk, and a bag like structure at the stalk’s base. While all mushrooms are perfectly safe to touch, you’d never want to eat a death cap – they can cause acute liver failure. Mushroom enthusiasts, especially novice ones, must be aware of the death cap.

Our group walked into a redwood grove near the Canyon Meadows Staging area. We quickly found coral fungi, which really do resemble undersea corals, and rabbit-foot inkcap (Coprinopsis lagopus) a mushroom that auto-digests and turns to black mush as it releases its spores. Trent pointed out a group of candy caps (Lactarius rubidus), reddish-brown mushrooms that were growing at the base of a redwood. They are members of the Lactarius genus, a group that oozes milky latex when flesh is disturbed or scratched. Candy caps are known for smelling strongly of maple syrup, and their sweet smell and edibility make them a tasty addition to cookies and other desserts. Trent emphasized that it is illegal to gather mushrooms and take them from East Bay Regional Parks since this activity further disturbs the already beleaguered area.

Redwood rooter (Caulorhiza umbonata). Photo: Trent Pearce

Redwood rooter (Caulorhiza umbonata). Photo: Trent Pearce

Saprotrophic fungi release enzymes that break down organic material like leaf litter and dead wood so they can absorb amino acids and other nutrients. Redwood rooters (Caulorhiza umbonata), which are very common among these trees, are saprobic upon leaf letter. Trent plucked a large one from the soil so he could share the long taproot-like structure that rises from deep within the soil. He pointed out the caps of two redwood rooters. The younger one had a smooth, oval shape, while the older was flatter and frillier since the mycelium had flooded the mushroom with water, making it very photogenic.

Boletes also thrived in damp gorge of Redwood Creek. These mushrooms lack gills; their spores develop in tubes that fill spongy surfaces on the bottom of their caps. Trent shared a Suillus, a slimy bolete that looks quite haggard after a few days. He recommended that mushroom enthusiasts learn to identify the fruiting bodies during different stages of their short lives. Waxy caps, which have thick, widely spaced gills and bright, slimy caps sprouted nearby. Trent promised that the hike would end with a surprising group of waxy caps.

“This is one of the easiest wild mushrooms to identify,” Trent said, showing a broad, white mushroom that grew from a rotting log. The oyster mushroom (Pleurotus ostreatus) gets nutrients by breaking down wood from dead trees, but there is also some evidence that it and other saprotrophic fungi can parasitize living plants as well. This is one of the most popular edible mushrooms and many enthusiasts raise it at home on mulch, cardboard – anything that’s wood based. “They grow quickly, almost as soon as a raindrop hits them,” Trent said.

Deadly galerina (Galerina marginata). Photo: Trent Pearce

Deadly galerina (Galerina marginata). Photo: Trent Pearce

Back in the forest, Trent pointed out a deadly galerina (Galerina marginata), a small brown fungi growing from wood. It vaguely resembles a candy cap but produces the same toxins as the death cap, making it deadly poisonous. Since it isn’t a Lactarius, it doesn’t bleed latex and doesn’t smell like maple syrup. People who gather edible fungi must learn to distinguish between these species. It isn’t clear why some fungi are poisonous; the compounds may simply be the byproducts of the organism’s digestive process as it secretes enzymes that break down plant material so the mycelium can absorb  nutrients.

At the walk’s end, Trent enthusiastically shared a group of small, orange waxy caps. “My friend who is writing a book about California’s coastal fungi says these have never been described in the literature,” he said. The parrot mushroom (Gliophorus psittacinus), which has a beautiful green waxy cap, is their closest relative. They may be a subspecies of that fungus, but mycologists suspect they could be a new species since parrot mushrooms show different coloration and cap features. Genetic sequencing will eventually reveal the truth. “This is only their second observation in the East Bay!” Trent said.

Undescribed waxy cap (Gliophorus fenestratus nom. prov.). Photo: Trent Pearce

Undescribed waxy cap (Gliophorus fenestratus nom. prov.). Photo: Trent Pearce

“Mycology is exciting to me,” Trent said, “because there are so many unknowns.” Mycologists estimate that between one and three million fungal species may exist, but only about one hundred thousand have been described by science. “It is hard to find new species of birds or trees, but there could be new species of fungi in your own back yard. You don’t have to have a PhD either, you can make valuable contributions to science with citizen observations.” Keep your eyes open and your camera clicking!

For more fantastic photos of mushrooms, check out Trent’s website: Left Coast Naturalist!

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