Types of Fungi: Mushrooms, Toadstools, Molds

Fungi are as important to our lives as wheat, cattle, fish or any other living thing.

Here are just a few of the reasons to admire this life form:

• Without the various types of fungi on Earth, we would soon be knee-deep in dead leaves that refused to rot.
• Trees that died would just continue to lie where they fell. Only fungi can break down lignin, the tough material at the heart of woody tissues.
• Our crops would fail because the nutrients that fungi recycle from dead plant tissues would no longer be available.
• Important farm animals, like sheep, are unable to digest grass without a little help from some friendly fungi.

And then there is the sheer beauty of many of these organisms...

What would our woods and fields be like without all those beautiful mushrooms and (sometimes, sinister) toadstools in the fall?

So, this page takes a look at a very important group of living things that, on the whole, we should all be grateful for.

What Exactly are Fungi?

Scientist used to place fungi in the Plant Kingdom, mainly because they were thought to be incapable of moving under their own power. Closer study shows that at least some fungi have reproductive stages with gametes that can swim.

The most obvious difference to plants, though, is that Fungi do not make food from sunlight and carbon dioxide. Fungi use food in a similar way to animals, digesting and absorbing what they need in the environment.

Nowadays, fungi are given their own Kingdom.

Within the Fungi Kingdom, these are the most important sub-divisions or 'Phyla':

• Basidiomycota: the mushrooms and toadstools.
• Ascomycota: sometimes called sac fungi. These often have vivid eyecatching fruiting bodies. This group includes the very tasty morels (see below) and truffles. It also includes the penicillin species which gave us the first effective antibiotic.
• Neocallimastigomycota: These live in the digestive tracts of plant eating animals like sheep. The enzymes that they produce break down polysaccharides like cellulose- the tough material that gives plants their strength. The sheep can then use the simpler carbohydrates that are produced as food.
• Blastocladiomycota: mostly soil dwellers that digest detritus of all kinds
• Glomeromycota: a very specialized group of Fungi that live in a beneficial symbiosis with Liverworts(small plants similar to mosses).
• Chytridiomycota: an ancient group of fungi that digest tough proteins like keratin (common in skin and hair) and chitin (especially common in the outer 'shells' of insects)
• Microsporidia: a small group of single-celled parasites that infect beetles, mostly

There is a closer look at the 2 most important groups, the Basidiomycota and the Ascomycota, below.

Basidiomycota is a large group and the one we are most familiar with. It includes:

• mushrooms
• puffballs
• stinkhorns
• bracket fungi
• jelly fungi
• boletes
• smuts
• bunts
• rusts
• chanterelles
• earth stars

Mushrooms are one of the most noticeable groups of fungi. Most of the fungus is hidden from view in soil, leaves or deadwood (depending on the species). The large fruiting bodies that emerge, mostly in the Fall, are conspicuous and often very beautiful.

Some mushrooms are even bio-luminescent, as you can see below.

Like most fungi, Basidiomycota are saprotrophic, which means they decompose dead matter including the toughest of plant materials like lignin, a major structural component of trees.

Underground, the Basidiomycota produce large networks of tiny tubes called hyphae. These grow through dead plant and animal material by secreting enzymes that dissolve a pathway. The digested material is absorbed and used as food.

The fruiting bodies we see above ground disperse spores which develop into new individuals.

Some of these fruiting bodies make a very good meal- like the russulas pictured above. Some will make you very sick, like the Amantia, shown below.

Exercise caution!

Ascomycota is the largest phylum of Fungi, with over 64,000 species. There are 2 main groups.

Pezizomycotina

Pezizomycotina fungi have fruiting bodies similar to mushrooms and include morels, truffles, ergot and cup fungi.

Truffles (Tuber genus) are one of the most expensive foods on the planet. It is impossible to grow truffles on a large scale and they are very rare in their favorite woodland habitats.

Pigs or dogs with especially sensitive noses are required to locate the much prized underground fruiting bodies.

White Truffles currently cost around $5 per gram ($2,000 per pound)

Saccharomycotina

This group comprises most of the yeasts, including the very important, baker's yeast.

The white bloom on grapes (picture below) is a mixture of wild yeasts and molds.

In the past, natural yeasts present on grapes were relied on to ferment the juice and produce wine.

Nowadays, commercial winemakers usually innoculate grape juice with a high dose of a single variety of specially grown yeast like Saccharomyces cerevisiae, rather than relying on the slower growing wild yeasts.

Whichever yeasts are used, the process is essentially the same. Yeasts consume sugar (without needing oxygen) and produce alcohol and carbon dioxide in the fermentation process.

Harmful Fungi

Most fungi are beneficial. Mushrooms make wonderful food. Yeasts help us with the most basic food stuff- bread. The detritus eating fungi keep our crops supplied with nutrients by efficient recycling.

There are some fungi that are harmful to humans, however.

• Athlete's Foot is caused by the Fungus, Trichophyton.
• The spores from molds can cause respiratory problems in the home. See: cdc.gov/mold/stachy.htm
• Some Ascomycota like the powdery mildews, are a serious problem for gardeners and farmers, especially in wet years.
• Late potato blight is caused by Phytophthora infestans, which is not a true fungus but very closely related. It, and other water molds, turn plant tissues to mush. In the 19th Century, most of the human population in Ireland relied on potatoes for food. Potato blight wiped out crops and millions of people died, or were forced to emigrate.
• Fungus, especially molds, can affect prepared foods like bread, fruit preserves, pickles and cheese. If the mold has penetrated, deeply into the food it needs to be discarded.
• Ergot is an interesting fungus that can thrive in stored cereals like rye if it becomes damp.The hallucinations and convulsions that Ergot ingestion produce were responsible for 'Saint Anthony's Fire' in the Middle Ages. Whole communities could be seized with strange symptoms often ascribed to witchcraft.
• Dutch Elm Disease has been responsible for the deaths of millions of elm trees around the world. A beetle bores under the bark of the tree and a fungus it carries invades the inner tissues.
• A few species of fungi can be fish parasites affecting farmed and wild fish.

Wood Decay Fungus

The types of fungi that cause wood decay are important in recycling nutrients from fallen trees but are a menace in homes and other buildings.

Wood decay fungi are usually broken into three groups:

• Brown rot fungi that produce hydrogen peroxide which attacks cellulose.
• Soft rot fungi that produce an enzyme called cellulase which digests cellulose
• White rot fungi that produce enzymes capable of digesting lignin.

The complete decay of dead wood involves many kinds of fungi.

Despite the damage that fungi can do in homes and the food we lose to molds, I am staying with my original statement. Fungi, overall, are good for us and we should be grateful for them!

Some of these are beautiful, some a little sinister!

A number of these fungi are edible but you should never eat any fungi without expert advice. Many people die each year as a result of eating poisonous species.

The Indigo Milk Cap is from the Russula family. It is found in all kinds of woodland.

In many countries like China and Mexico, it is eaten.

It can be found in the US and Europe.

Sheathed Woodtuft (Kuehneromyces mutabilis) grows on decaying wood. It is not only provides a wonderful bright spot in a wood, it is edible and very tasty.

It is a common species, in cooler climates, worldwide.

Tremella mesenterica (above) is a bright yellow or orange 'jelly' fungus that grows on trees.

Some of its unflattering names include 'yellow brain' and 'witches butter'. Some more poetic names are 'golden jelly fungus', and' yellow trembler'.

Clavaria zollingeri (above) is usually found in leaf litter or grasslands. It is a widespread fungus but in the US, you will only find Clavaria in the Northeastern forests.

Hydnellum peckii has some sinister names, including the bleeding tooth fungus, and the Devil's tooth fungus but at least it is not poisonous.

I think it is rather attractive!