Fungi have a long and complex history on planet Earth. In 1779, a type of bio-luminescent mushroom was used on the first submarine to light up the instruments. The common Oyster mushroom operates at a microscopic level to poison, kill, and digest nematodes. Fungi like Massospora take over and transform Cicadas into flying spore factories. Others like Ophiocordyceps use Carpenter Ants as their preferred fruiting substrate. And currently the largest living organism on Earth is an Armillaria species – Honey Mushroom – in Oregon. Fungi can filter waste from the soil in watershed areas. They can produce chemicals such as Vanillin not previously found in fungi. They can be used to create packaging material, and in burial shrouds to decompose the deceased. They can create novel chemicals to fight pathogens and control animal behavior. There’s very little fungi can’t do.
What is a fungus? A fungus is a member of the Kingdom Fungi, which includes nearly 150,000 “spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools.”i “A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms”ii
So, then… What is a mushroom?
A mushroom is a specific part of certain types of fungi. Yeasts are fungi but not mushrooms. Morels are mushrooms and therefore fungi. So all mushrooms are fungi but not all fungi are mushrooms. The term mushroom refers to the fruiting, spore-producing body of certain species of fungi. Although many mushrooms include gills, other include pores, spongy surfaces, teeth, and pits, all of which are mechanisms for releasing spores. And the shapes can vary from the common “toadstool” shape to brackets, blobs, pom-poms, and much more. These fruiting bodies are also the most commonly used parts of fungi for food and medicine.
So getting back to the idea of Spores… the spores are the genetic material fungi use to reproduce. Just like any other organism on Earth, the main goal of fungal species is to spread and expand. Mushrooms do this be producing spores, which are haploid entities. Meaning they have half of the genetic material needed to reproduce. So a spore needs another spore. While it may seem simple, mushroom spores can have thousands of what humans call “genders” so the genetic possibilities become much more comples.
However, for the most part, when two compatible spores meet they will form a hypha. This is the beginning of the fungal organism taking life. Once a hypha exists, it can utilize the materials around it to grow more hypha, becoming hyphae. At this level, the fungus is still capable of incredible behavior. Oyster mushroom hyphae can have a toxic tip which infects certain nematodes. Once the nematode is infected and paralyzed, the fungus can digest it from the inside out and use the nutrients for growth.
Once enough hyphae chains together, the result is mycelium. Mycelium is when we start to see structural materials being formed at levels visible to the naked eye and what ultimately gives rise to the fruitbodies, or mushrooms. Mycelium uses nutrients from the surrounding medium and compounds it makes itself to spread and digest its preferred substrate – wood, soil, deceased insects, grasses and straws, manure… the list is endless. And if you dig up any part of the forest floor in any forest you are guaranteed to find some type of mycelium. Most likely several to several hundred types. But more on the Mycelial Network later…
When conditions are right to “fruit,” the mycelium will compact and form the fruiting body – the mushroom. However even this can happen in vastly different fashions depending on the species. The Oyster mushroom will simply colonize whatever substrate is available. Once the mycelium has taken over and has the maximum surface area exposed to oxygen, it will begin to produce the Oyster mushrooms. As long as conditions are right, this will continue until the substrate has been fully consumed.
However, there are fungi such as Chaga that follow a completely different rulebook. Chaga grows on living Birch trees. Usually around 1 in 10 million will contain Chaga so it is not terribly common in the grand scheme of things. Chaga will remain in a “sterile” form for most of its life. It forms an odd looking black conk with a gold interior, emerging from the living tree. It is alive although it grows so very slowly – around 1 cubic inch per year, vs the Oyster which can complete its full spore-to-fruit cycle in a matter of weeks. However when Chaga senses that its host tree is dying, right before the death, the Chaga will “fruit”, creating a series of microscopic fruiting bodies that exist for 48 hours or less. During this window is the Chaga’s entire opportunity to release spores and hope they find a new living host.
So what can mushrooms do? Of course they can be food. Most grocery stores have the familiar “button” mushrooms, and usually Portabellas. These are the young and mature versions of the same Agaricus species. But there are hundreds of species that can be either cultivated, wild-harvested, or both. It’s quite easy to cultivate shiitake, Oyster, Lion’s Mane, and Chestnut mushrooms on logs, sawdust, or other media. And in addition to being found in the wild, western NC has some amazing species such as Morels, Chicken of the Woods, Blewits, Enokis, Maitakes, Hedgehogs, Chanterelles, Black Trumpets, Brick Tops, certain Boletes, and much much more.
However you should NEVER pick and consume a wild mushroom unless you have an expert’s sign off. Some edible mushrooms look like those which aren’t so edible and without proper training you can be confused. Don’t rely on a book or an app… find a forager to take you walking and educate you in person.
For those who want to cultivate mushrooms there are a lot of options. Making shiitake logs is fun and will yield a nice harvest a couple times each year. You can also easily grow Oysters on straw and Lion’s Mane on supplemented sawdust. There are low-tek methods that don’t require a big investment or any special equipment. Of course it’s possible to create larger grow operations with more capacity but the startup cost is high and this is when specialized equipment comes into play. However most such operations are mushroom-only, whereas the “low tek” methods can be easily incorporated into most existing farms or households.
Many mushrooms which wouldn’t normally be food, and a few that are, end up being amazing medicine too. Reishi, Lion’s Mane, Maitake, Shiitake, Turkey Tail, Birch Polypore, the Milk Cap family, and Cordyceps just to name a few. Of course there are proven immune benefits to using medicinal mushrooms, but there are also unique fungi such as Lion’s Mane. The compounds created by this mushroom increase Nerve Growth Factor production, and help to re-establish myelin on damaged nerves. Nothing else we know of in nature can accomplish this. However some recent studies by Yale have shown that the psilocybin found in some mushrooms can stimulate dendrite growth in rats within 24 hours of a single dose.
We have also watched mushrooms such as the shiitake develop novel compounds to overcome viruses, bacteria, etc. You can put some shiitake mycelium onto an agar plate and introduce a pathogen of some sort. Eventually the two organisms will create a boundary; after a couple days, the shiitake will more than likely have created a compound which allows it to overtake the competitor. Obviously you can’t see the chemistry in action but you can see the result. Krestin, a top-selling anti cancer drug in Japan, was originally found in Turkey Tail mushrooms.
One of the most amazing things about mushrooms – the actual fruitbodies – is that they represent only a small part of the living organism. The fungus stays alive 365 days a year but the mushrooms it produces may only last days, or in some cases, hours. So what is going on with all that mycelium we don’t see? More than you could possibly imagine.
We now know that every plant or tree growing in the wild has fungal partners. It becomes impossible to separate plant roots from mycelium. And at the microscopic level, there are “epiphytes” – fungi that live inside the plant cells. So what are they doing? Communication and resource allocation are huge tasks. The mycelium can “mine” certain minerals from the soil and make it available to plants. Plants, in turn are able to provide Carbon to mushrooms. See, fungi breathe like humans – Oxygen in, Carbon Dioxide out. So a fungi’s biggest issue is losing Carbon. Plants, on the other hand, create Carbon during photosynthesis. They can exchange that Carbon, with a nutrient such as Phosphorus, that is more accessible to the fungi.
What’s interesting is that this can occur across huge sections of natural area, and between species. A species such as a Fir that creates more Carbon in the Spring, will need more in the latter part of the year when the forest canopy overshadows it. So when the Fir is producing the most Carbon, mycelium will transport it to Birch trees, who have yet to dawn their leaves. Then as the Birch comes to seasonal maturity and reaches its own Carbon maximum, the mycelium will transport Carbon back to the Fir.
Fungal mycelium can also make decisions based on what we would call an exchange rate. Imagine a large plot of land which is rich in Phosphorus at one end and Phosphorus-poor at the other. The region with less phosphorus therefore considers it more valuable, and will require more Carbon from its plant partners in order to exchange. Knowing this, the mycelium will transport its Carbon from one area to the other, to take advantage of this more favorable “Exchange Rate.”
And last but not least, lichens. Lichens are complex beings. For many years, they were thought to be the combination of a fungus and an algae. While this is partially true, we now know that Lichens are often made up of several, or more, organisms. Not just a fungus and an algae, but a bacteria, and perhaps a second fungi…. What’s so fascinating is that these organisms can survive conditions nothing else can. Certain lichens exposed to extreme temperatures, droughts, and even cosmic radiation can be successfully rehydrated, revived, and resume reproduction. One experiment exposed Lichens to the conditions of outer space, well above Earth’s atmosphere – some species survived and were able to be revived once back on Earth.
Thanks for being here today. I hope you learned something new, and had a little fun. With that, I will leave you with one question… what can’t fungi do?