Fungi with a Fun Guy

“Can you eat it?”

“Will it kill my plants?”

Beyond these two initial questions, most gardeners aren’t particularly drawn into the mysteries of the fungi kingdom. However, when Dr. Don Hemmes, foremost authority on fungi of Hawai'i, amiably spreads his abundant enthusiasm around like mycelium proliferating the soil of a thriving forest, one can’t help but want to learn more about this amazing group of living organisms.

Hemmes teaches biology at University of Hawai'i at Hilo and is co-author of Mushrooms of Hawaii, a layman-friendly reference book based on years of scientific research. On this uncommonly hot, sunny February day, he led the Hawai'i Island Master Gardeners on a magical mystery tour of mushroom heaven, otherwise known as MacKenzie State Park, not far from the active lava flows of Kalapana. (Hey man, no need to call anyone, we weren’t looking for cow-patty hallucinogenic mushrooms here, ‘kay?)

Normally there are copious mushrooms at MacKenzie due the moist windward coastal environment and the ubiquitous ironwood trees (Causurina) that make hospitable substrates of loose, thick duff for mushrooms to grow in. Even though the weather was a welcome change for most people who had to deal with the recent Hilo flooding, the dry weather did make pickin’s slim for mushroom hunting on this particular outing. We found some interesting dried-up specimens, of course, but we also came across some living wood fungi as well as a few mushrooms that sprouted earlier in the day.

Here are some of the fruiting bodies we saw…

Pycnoporus sanguineus, used by weavers to make a yellow dye...

Inky Caps (Coprinus lagopus) on a fallen coconut log….

Turkey Tail (Trametes versicolor)…

Earthstar, dried (Geastrum sp.)

Dried-up Green-spored Parasol (Chlorophyllum molybdites). EXTREMELY toxic…

Only 5 percent of Hawaii’s mushrooms are edible and tasty. Another 5 percent are so toxic that if you eat them “you’ll be dead, or wish you were” because you’ll be vomiting violently, nonstop, says Hemmes. The rest of the mushrooms just taste terrible. Should you taste them anyway? Nope, not unless you are an expert who can ID to species, or you are with one, or you are looking forward to a liver transplant and a lifetime of medication, or you’ve updated your will.

Our native forests, mostly above 4,000 feet elevation, have only native mushrooms – about 300 identified by Hemmes, all given Hawaiian names with the help of UHH Hawaiian Studies department chair Kalena Silva. Ninety percent of Hawaii’s native fungi are endemic.

Although many mushrooms have distinctive characteristics that make them easy to identify, many are difficult to distinguish and a single mistake could be deadly. In fact, the fatally toxic Amanita marmorata, which often pops up in public parks, schoolyards, and suburban lawns near eucalyptus, paperbark and ironwood trees, is a dead ringer for the white button mushrooms sold in grocery stores and as pizza toppings. If a mushroom mix-up lands you in the hospital in Hawai'i, you’ll be getting a visit from Dr. Hemmes since he's on every hospital's list for consultation – not the way you would want to make his delightful acquaintance, but certainly you would be extremely fortunate to have his invaluable expertise and upbeat demeanor to aid your recovery.

Fungi play vital roles in the garden. Some are decomposers that break down organic matter and free up nitrogen in the nutrient cycle, others can be mycorrhizal types that aid plants in their uptake of water and nutrients. While some fungi are parasitic and kill plants, or can just be a nuisance and cause a stink in your yard, many might also have unique properties that are proving to be useful in medicine, agriculture, environmental remediation, and other human interactions.

Of the world’s 2 million species of fungi, Dr. Don Hemmes has identified 75,000. He’s always on the lookout for new species, so if you find something interesting in your garden or on a hike, send him a digital photo via email at hemmes@hawaii.edu.