Fun Facts About Fungi

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Mushrooms: launching pads for spores


Why Study Mushrooms

There are several reasons I study mushrooms and other fungi. I am fascinated by their biology and the way they interact with other organisms. Some decay logs, others are the partners of living trees (see mycorrhizae). Some mushrooms form fairy rings that may be huge and hundreds of years old. Others are an important food for squirrels, mice, deer and other animals. They can live almost anywhere. Their fruiting bodies develop in a huge array of forms and colors, many quite beautiful.

I enjoy collecting mushrooms because it gives me a chance to walk in the woods and enjoy this rich habitat. I test my skills of observation and my personal knowledge of fungi, and also have the pleasure of observing the life in the forest around me.

Like any treasure hunt, finding mushrooms is a combination of knowledge and luck. Some people collect and identify mushrooms for the pleasure of studying them, the way bird watchers enjoy studying birds. Most people hunt for edible mushrooms. Many are good to eat and some are especially delicious, such as morels and truffles. "How to Collect and Identify Mushrooms" has detailed information for the beginning collector. NO BEGINNER SHOULD EAT ANY MUSHROOM THAT HAS NOT BEEN IDENTIFIED WITH THE HELP OF A LOCAL EXPERT.

What is a Mushroom?

Mushrooms are the fruiting bodies produced by some fungi. Not all fruit bodies are true mushrooms. Puffballs and morels are edible fruit bodies that are sometimes called "mushrooms". The function of this visible part of some fungi is to produce and disperse the largest possible number of spores in the shortest possible time. Spores create new individuals after being carried away on the wind and landing in a good place for growth.

True mushrooms typically look like umbrellas. They consist of a stalk topped by a flat or cup-shaped cap. Their spores are produced on special cells called basidia, located on the underside of the cap. The class of fungi whose spores are produced by basidia are called Basidiomycetes.

People often ask about the difference between toadstools and mushrooms. Any mushroom can be called a toadstool, but this word usually refers to a poisonous mushroom.

What do they look like?

Click the link to see some photographs of mushrooms with gills and mushrooms without gills.

Life History of Mushrooms

While mushrooms may seem to sprout overnight, it actually takes days or weeks for one to develop. Most of the growth of a fungus goes unnoticed because it occurs underground. The underground body of a fungus, called the mycelium, is made of moist thread-like filaments called hyphae. When growing conditions are good, little knots of hyphae called primordia are formed. As individual primordia grow larger, the hyphae within them organize into two parts. One part will become a mushroom’s cap, and the other, its stem.

mushroom growth animation

When the primordium gets large enough, the stem elongates and pushes the cap up above the ground. As the stem elongates, the cap expands, a little like an umbrella unfolding. In some mushrooms, the expanding cap breaks a veil-like membrane extending from the cap to the stem, leaving a ring. Some growing mushrooms may also break a second membrane that covers it completely, and dried bits of this broken veil form scales on the cap.

Parts of Mushroom

On the underside of the cap, the spore-producing basidia are found in several different structures. Basidia may cover the surface of tissue-thin hanging plates called gills, or line the inside of tubes, or cover "teeth".

Basidia produce four spores at the end of microscopic spines called sterigma. When the spores are ready, they are discharged a short distance into the space between the gills or teeth, or into the center of the tube. The spores then fall out of the cap and are carried away in the wind. Most spores land within three feet (1 m) of the mushroom that produced them, but they can be carried much further. If the spore lands in a good spot, it germinates, producing the mycelium of a new fungus individual.

basidium animation

The puffballs are relatives of mushrooms whose basidia and spores are enclosed in a sac instead of covering gills, or in tubes. Coral fungi are also mushroom relatives. They produce branched fruiting bodies that resemble coral or broccoli.

puffball

Despite producing large mushroom-like fruiting bodies, morels and false morels are not closely related to mushrooms. These fungi are related to the cup fungi, in the class Ascomycetes. Their spores are produced inside a special cell called the ascus, instead of on the outside of basidia. The spores of morels and false morels are explosively discharged into the air as a fine white cloud.

Where do Mushrooms Grow?

Mushrooms and other fungi grow almost everywhere, on every natural material imaginable. Where you look depends on the mushroom you are trying to find. Some fungi grow only in association with certain trees. Others grow on large logs. Mushrooms are also found in soil, on decomposing leaves, and in dung, mulch and compost.

Knowing when to look is also important. Mushrooms are not formed until temperature and moisture conditions are right for them. Some mushrooms are produced during only one season of the year. During mild or warm weather, they often appear 7 to 10 days after a good rain.

ascospore discharge

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Last update: 23 Nov 97. © 1997, Robert Fogel, Ivins, UT 84738. Edited by Patricia Rogers.