Mushrooms and Other Fungi
Decomposition is a fundamental process on which all life depends. When a plant or an animal dies, the energy stored in them is not lost. Bacteria, fungi and other microscopic organisms produce special enzymes to break down dead plants and animals so they can use them as food. These organisms, called decomposers, live in the soil, air and water. They are nature’s recyclers.
Fungi is one important decomposer. Fungi is a major kingdom of living things. They do not have chlorophyll like plants, so they can’t photosynthesize their own food. Like other decomposers, they rely on other plants for their nutritients.
All fungi have a vegetative body called a thallus or soma, composed of hyphae. The hyphae typically form a microscopic network within the mycelium, through which food is absorbed. Usually the most conspicuous part of any fungus are its fruiting bodies—reproductive structures that produce spores.
Some fungi are used in medication. Penicillium is a fungus that kills harmful bacteria in the human body. Yeast is a useful fungus used in bread-making and for making beer and wine.
Mushrooms are the fruiting bodies of certain fungi. They occur in all environments on the planet. Some mushrooms are parasitic. They colonize living trees or plants, extracting nutrients until the host slowly dies. Saprophytic mushrooms live off organic matter that has already died and begun to decay.
Mushrooms like to live in dark, damp places. They feed off the decaying matter around them. As the mushroom grows, it develops spores. New mushrooms grow from these spores. The spores are so tiny you can’t see them without a microsope. Millions of spores together look like fine powder. A mature mushroom will form as many as 16 billion spores.
When the spores are ripe they shoot out of the mushroom and drift away in the wind. If they land in a dark, damp place with a food source, they will grow into new mushrooms. First, they develop a threadlike structure called a hyphae. A large number of hyphae grow together and form the mycelium. The hyphae and mycelium grow under the surface where you can’t see them. The fruiting body is the part of the mushroom that appears above ground. When it first appears, it looks like a little button.
The fruiting part of the mushroom that we see is only a small part of the mushroom. The entire body of a mushroom is usually spread out over a large area. In nature some species of mushrooms may have a body that spreads over hundreds of square miles. A population of honey mushrooms in the Blue Mountains of eastern Oregon was found to be the largest single organism in the world, spanning 2200 acres.
There are 38,000 different varieties of mushrooms, with 3,000 in North America. Not all mushrooms are edible. In fact, some mushrooms are poisonous, so you should NEVER EAT MUSHROOMS growing in the wild.
Mushrooms were first cultivated in Southeast Asia. Mushroom farming first started in the US in 1896 in Kennett Square, PA. Two florists, William Swayne and Harry Hicks, wanted to make use of empty space under the shelves where they grew their flowers. Flowers need sunlight, but it was very dark and damp under the shelves. They couldn’t grow flowers there, but they could grow mushrooms, since mushrooms don’t need sunlight to grow.
Mushroom farms today are climate-controlled buildings with airflow, temperature and light all constantly monitored. The most common mushroom raised for eating is the white button mushroom. Shitake, enoke and oyster mushrooms are some other varieties raised for eating. Most grocery stores in the western world sell button mushrooms canned and fresh. In Miami, Oklahoma, J-M Farms, Inc., produces button mushrooms that are sold in Oklahoma, Texas, Arkansas, Mississippi, New Mexico, Kansas, Missouri and Iowa.
The Portobello mushroom is a large brown strain of the same fungus as the button mushroom, left to mature and take on a broader, more open shape before picking. Portobello mushrooms are distinguished by their large size, thick cap and stem and a distinctive musky smell. Portabello mushrooms serve as a substitute for meat in some recipes because they have a similar texture.
The shiitake (she-TAH-kee) mushroom is large and brownish to very dark brown and has a fleshy cap from about 1 to 2 inches across. Shiitake are easily dried, convenient to use and inexpensive to store and transport. The shiitake mushroom is native to Japan and China and grows naturally on fallen oak logs in the spring and autumn. Shiitake is from the Japanese shii for oak and take for mushroom. In China it is also called the hsaing ku, meaning fragrant mushroom. Shiitakes are the second most-consumed mushrooms in the world, after the button mushroom. In Asia it is number one. Shiitake mushrooms are Japan’s number one agricultural export. Shiitake can be grown either on hardwood logs like oak or on a special combination of oak sawdust, bran, millet and other additives. In Oklahoma, Lost Creek Farms in Perkins produces shiitake mushrooms and shiitake mushroom log kits for people who want to grown their own. Logs usually average 4-6 inches in diameter and 40 inches in length. Spawn, or mycelium, is placed in pre-drilled holes. Wax is melted and dripped over the hole to form a seal.
Although a mushroom is not a true vegetable, the National Agricultural Statistics Service (NASS) includes mushrooms in the vegetable category for statistics purposes. Mushrooms are a good source of potassium. The US is the second largest producer of mushrooms, following China.
Students will listen to a reading of a poem that describes how mushrooms grow and guess what the poem is describing, discuss the poem and answer comprehension questions, read an informational passage describing how mushrooms grow and compare the informational passage with the poem. (Grades 3-5 ELA)
Students discuss the differences between plants and mushrooms and compare the functions of parts of a flower with parts of a mushroom. (Grades 3-5 Life Science)
Students conduct an experiment with a variety of mushrooms to discover the colors their spores produce. (Grades 3-5 Life Science)
Students learn the role of fungus in decomposition, list the steps in mushroom production, draw a model showing the life cycle of a mushroom, design and conduct experiments with mushroom compost. (Grades 3-5 Life Science)
Students will conduct an experiment with bread to observe the growth of fungus. (Grades 3-5 Life Science)
Student observe decomposition of a pumpkin. (Grades 3, 5-6: Life Science)
If you used these lessons, along with the "Fruits, Nuts, and Veggies, Oh My" booklet, please let us know by answering a few quick questions. Your class might be featured on the website as a result!
Farrell, Jeanette, Invisible Allies: Microbes That Shape Our Lives, Farrar, Strauss and Giroux, 2005. (Young Adult)
by Sylvia Plath
Our toes, our noses
Nobody sees us,
Soft fists insist on
Even the paving.
Diet on water,
Little or nothing.
We are shelves, we are
Nudgers and shovers
We shall by morning
Oklahoma Ag in the Classroom is a program of the Oklahoma Cooperative Extension Service, 4-H Youth Development, the Oklahoma Department of Agriculture, Food and Forestry and the Oklahoma State Department of Education.