Brett Anthony Bowen, age 13, of Enid, Oklahoma, for his question:
How does a mushroom grow?
In regions where winters are mild, crops of wild mushrooms often pop up in the fall. And everybody wants to know how to tell the edible mushrooms from the poisonous toadstools. The answer is simple and definite. None of these wild fungus plants are to be trusted as human food. Mush¬room experts are rare and sometimes even one of them makes a mistake. Besides, the wild brothers of the cultivated mushrooms are almost sure to be infested with bugs or otherwise contaminated.
Most plants use the energy of light to manufacture their basic food from carbon dioxide and water. Members of the fungus family do not have the green chlorophyll necessary to perform this miracle called photosynthe¬sis. The mushrooms are fungi and because they are unable to carry on photosynthesis, their life style is very different from that of the average green plants.
Though a mushroom cannot manufacture them, it needs rich organic plant chemicals to thrive and grow. Since only green plants can provide these special hydrocarbons, the mushroom depends on decaying vegetation found in moist, humus type soils. The fact that it needs no sunlight, gives the mushroom plant a special advantage. It can grow out of sight, just below the surface of the soil. It needs no leaves and no stems.
Actually the main mushroom plant is a tangled mat of pale, fleshy threads. The shaggy underground rug is called mycelium. It absorbs and assimilates dissolved chemicals and builds more threads of mycelium around its spreading edges. This underground growth goes on as long as the rich soil is moist and fairly warm.
However, the secretive plant cannot remain hidden forever. Once or twice a year, it must try to multiply. The mycelium sprouts a crop of fat buttons that poke above the surface and become those chubby little um¬brellas that we call mushrooms. Actually they are the fruiting bodies of the true mushroom plant, which is the mycelium.
The underside of each umbrella is packed with delicate folds of gill tissue. Tucked among these dainty ribbons there are perhaps two billion tiny spores. When the spore seeds are ripe they prepare to leave home ¬and at the right moment, clouds of them take off on a friendly breeze. Most of them fail to find a suitable landing place.
Maybe one lucky mushroom spore in a trillion will fall in a moist shady spot where the super rich soil contains plenty of organic material, prefabricated by the world of green plants. It sprouts the few threads of mycelium that start a new mushroom plant.
Only cultivated mushrooms are grown under controlled conditions that keep out insects and other contaminations. None of the wild types can be trusted. Besides, one of the most dangerous fungus plants looks enough like a safe mushroom to fool anybody but an expert. It is called the death cup, alias the destroying angel names which indicate that one bite is almost sure to be fatal.