Eric Neal, age 11, of Richmond, Va., for his question:
HOW DO FUNGUS PLANTS ORIGINATE?
The most familiar fungus is the edible mushroom, now cultivated under hygienic conditions in special growing sheds. Meantime, wild mushrooms pop up unexpectedly in the meadows. There they have mystified people for ages because they arrive overnight. What's more, they often form a circle of their chubby umbrellas a bit of pixie type magic called a fairy ring.
The vast assortment of fungus plants is descended from single celled ancestors that appeared on earth perhaps half a billion years ago. They were among the earliest simple plants, but even then there was a great difference between them and most other plants. Green plants contain green chlorophyll. This is needed to use the energy of sunlight to manufacture
basic plant food from air and water.
The fungi have no chlorophyll and must depend on the green plants to prefabricate most of their food. For this reason, they must grow in soil that is rich in decaying vegetation and other organic materials. But they do not need to sprout food making foliage above the ground. In fact, the major part of a mushroom or toadstool is buried just below the surface. It is a tangle of threads called the mycelium.
Truffles and certain other fungi never poke their noses above the ground. But when the mushrooms and toadstools get ready to multiply, they sprout fruiting bodies above the surface. These chubby umbrellas come in pasty white, browns and various colors.
Under each umbrella is a lining of gill tissue, like delicate ribbons arranged in tight rows. Two billion or more tiny spores may be tucked into the folds of this gill tissue. The spore seedlets ripen and prepare to leave home. At the right moment, clouds of these dusty specks launch themselves on a friendly breeze.
Most of them are lost on the way. A new fungus plant originates when a lucky spore lands on a moist shady spot, where the soil is rich in decaying vegetation. It sprouts a few threads of mycelium and digs down to spread and stay.
A famous fairy ring originates when a mass of mycelium is buried with a long forgotten tree stump in the ground. It thrives on the rotting wood and sprouts its circle of fruiting bodies around the edge. The mycelium may thrive for centuries. As it spreads, the fairy ring of mushrooms grows wider year by year.