Too Many to Count


Story Behind the Science

Mushrooms and other fungi are neither plants nor animals.  In fact, fungi have an entire kingdom to themselves. Some say there are more than 1.5 million species of fungi, while others argue there are more than 5 million!  Either way, nobody is completely sure and there are certainly way too many to count.  That's only the beginning though.

When thinking of fungi, the most popular association is mushrooms. Mushrooms are only one type of fungi, though. They are the fruiting bodies made by some kinds of fungi, but not all of these fruiting bodies are considered true mushrooms. Morels and puffballs are often mistaken for mushrooms because of their fruiting bodies, but they are distinct types of fungi themselves. Other fungi include rusts, smuts, truffles, molds and yeasts.

Mushrooms and other fungi release spores for both survival and reproduction. When a nutrient source has been depleted and living conditions are no longer stable for a fungus, it will release spores that grow into fungi in another location where it can thrive. Spores can be specifically destined for places like the surfaces of plants and trees or on decomposed animals. They may also have specific dispersal methods, traveling by wind, rain or flowing water.


In the 2012 IUCN Red List of Threatened Species, there were almost 20,000 species listed, only three of which were fungi; two lichens and one mushroom. There are approximately 70,000 known species of fungi, but that is a small percentage of the estimated total of 1.5 million to 5 million species that have gone undocumented. Because most fungi have not been discovered, more of these unknown species may be threatened. One of the greatest threats to fungi is habitat destruction, especially among those that are dependent on a special host, which could be a specific type of plant, tree, animal or other fungi. For example, one of the world’s largest mushrooms, the nobel polypore, can only be found in old-growth forests in the U.S. Pacific Northwest. If these habitats are destroyed, or if a particular species in that area is endangered, a fungus that may prey solely on that habitat or species is also being threatened as a result.

Fungi are known as natural recyclers, as they perform an important function in nature: processing and decomposing dead organic materials. Also, fungi serve important functions among humans, as food and as a source for medicinal drugs. They are used in making foods like bread, cheese and beer, as well as in pharmaceutical drugs like penicillin.


Fast Facts

  • The word “toadstool” can be applied to all mushrooms, but it most often refers to a mushroom that is poisonous or inedible.Learn More »
  • Fungi make up their own kingdom and are more closely related to humans and animals than to plants.Learn More »
  • The associations between fungi and the roots of trees or other plants are called mycorrhizae.Learn More »
  • Mushrooms can produce trillions of spores in their lifetime.Learn More »
  • According to fossil records, at one time, fungi were present in Antarctica.Learn More »
Compare & Contrast Mushrooms Fungi
How many species? Approximately 20,000 (estimated total between 50,000 and 100,000) More than 70,000 known (estimated total between 1.5 million and 5 million)
Where do they occur? Mushrooms can occur on most natural materials in a habitat with proper temperature and moisture levels. Eighty percent of mushrooms can be found in woodland areas. Fungi occur throughout the world with diversity increasing in tropical areas. They are typically found on land, though few also live in water. Fossil records show that they were even present in Antarctica.
How do they grow? Mushrooms "eat" the organic materials they grow on. For example, they may feed on a tree or plant, logs, soil, decomposing leaves and dead animals or insects. Fungi grow into their food. They can be found in wood, soil, leaf litter, dead animals and animal waste, all of which they feed on. Some even have the ability to trap and break down nematodes and small animals.
Do they have predators? Squirrels, mice, deer and other animals Slugs, beetles, deer and other animals

BBC Worldwide, "Cordyceps: Attack of the Killer Fungi"