Not plants, not animals
Mushrooms grow in the ground like plants, but they are not plants. Fungi (singular: fungus) belong to their own kingdom. Surprisingly, DNA studies show that fungi are more closely related to animals than to plants!
There may be over 2 million species of fungi, but only about 150 000 have been named.
How fungi differ from plants
| Feature | Plants | Fungi |
|---|---|---|
| Food | Make their own by photosynthesis | Absorb food from their surroundings |
| Chlorophyll | Yes | No |
| Cell walls made of | Cellulose | Chitin (the same material as insect shells) |
| Store energy as | Starch | Glycogen (like animals) |
The hidden body of a fungus
The mushroom you see is only a small part of the fungus. It’s the fruiting body, which makes spores, like an apple on a tree.
- The main body is made of thin threads called hyphae.
- The hyphae form a huge underground network called a mycelium.
One honey fungus in Oregon’s Blue Mountains has a mycelium spreading across about 9 square kilometres. It may be thousands of years old and is one of the largest living things on Earth.
How fungi eat
Fungi release digestive juices into whatever they’re growing on, such as a log, soil or bread. The juices break down food outside the fungus, and the hyphae absorb the nutrients.
| Type | Food source | Example |
|---|---|---|
| Decomposers | Dead material | Mushrooms on rotting logs |
| Parasites | Living hosts | Athlete’s foot, Dutch elm disease |
| Mutualists | Partners that benefit both | Mycorrhizae, lichens |
How fungi reproduce
Most fungi reproduce with spores, tiny cells that drift through the air or water. One mushroom can release billions of spores. When a spore lands in a good spot (damp, with food), it grows new hyphae.
You can see the pattern of spores by placing a mushroom cap gill-side down on paper overnight. This makes a spore print.
Kinds of fungi
| Kind | Description | Examples |
|---|---|---|
| Mushrooms | Large fruiting bodies | Button mushrooms, chanterelles, puffballs |
| Mould | Fuzzy growth on food and damp places | Bread mould, Penicillium |
| Yeast | Single-celled | Baker’s yeast |
| Lichens | Fungi living with algae or cyanobacteria | Crusty patches on rocks and trees |
Why fungi matter
Decomposers
Fungi and bacteria are nature’s recyclers. Without them, dead leaves and trees would pile up, and nutrients would never return to the soil.
Partners with plants
About 90% of land plants have mycorrhizae: fungi that wrap around or enter their roots. The fungus helps the plant absorb water and minerals; the plant gives the fungus sugar. Fungi can even link trees together underground, sometimes called the "wood wide web."
Food and medicine
- Yeast makes bread rise by producing carbon dioxide bubbles. It’s also used to make soy sauce.
- Fungi help make cheeses like blue cheese and brie.
- Penicillin, the first widely used antibiotic, came from a Penicillium mould.
- Some fungi produce medicines that help organ transplant patients and lower cholesterol.
Harmful fungi
- Some wild mushrooms are deadly poisonous. Never eat a wild mushroom unless an expert has identified it.
- Fungi cause plant diseases that destroy crops.
- They cause athlete’s foot, ringworm and some lung infections.
- Mould in damp buildings can trigger allergies and asthma.
Common mistakes
- Thinking fungi are plants.
- Thinking the mushroom is the whole fungus. Most of it is underground.
- Thinking all mould is bad. Some moulds make medicines and foods.
Try it yourself
- Put a slice of bread in a sealed bag with a few drops of water. Observe it each day for a week (don’t open it). Draw what you see.
- Make a spore print from a store-bought mushroom.
- Mix yeast, warm water and sugar in a bottle, and stretch a balloon over the top. Watch the balloon inflate. What gas is being made?
Quick recap
- Fungi are their own kingdom: not plants, not animals.
- They absorb food and have cell walls of chitin.
- Their bodies are made of hyphae forming a mycelium.
- They reproduce with spores.
- Fungi decompose, partner with plants, and give us food and medicine.