Mary Jo DeGironimo, age 11, of Utica, N.Y., for her question:
HOW DO MUSHROOMS SEED THEMSELVES?
In the language of plant science, a mushroom is called a fruiting body because it bears seedlets for the next generation of mushrooms. The seedlets are called spores, and the average mushroom produces many millions of them. Usually we do not notice them because they are so tiny and the mushroom keeps them well hidden until they are ripe.
A mushroom plant begins life as a dusty little dark spore. It may be blown around by the breezes or dropped by a passing animal who has feasted on chubby round mushrooms. A trillion other mushroom spores come to nothing at all. But a lucky one may land in just the right spot to start growing.
The spot must be very special because mushroom plants have no green chlorophyll. This means that they cannot use energy from sunlight to manufacture sugary plant food from air and water. They must depend on the basic food manufactured by the green plants. They find this material in compost rich soil where plant material is decaying. One good spot is around an old rotting tree stump.
Our lucky mushroom spore is even luckier if the rich, loamy soil has plenty of moisture and a little shade. Then the tiny seedlet, no bigger than a grain of dust, sprouts skinny little threads down into the soil. No, these are not roots. These pale matted threads are called mycelium and actually they are the mushroom plant.
The mycelium thrives below the surface, using material from compost and decaying plants to build itself in a sizable mat of tangled threads. When the underground plant is grown and the weather is mild and moist, it gets ready to multiply. Here and there it sprouts up a thick little wad of pale tissue.
Each little wad soon grows a bump on its head. The stem grows thicker, and the bump becomes a button mushroom. In a few days, the button becomes a recognizable mushroom, looking like a chubby umbrella. The underside of the round top is crowded with dark papery strips of tissue. These are called the mushroom gills. And the spores for the next generation are tucked among the delicate folds.
When the spores are ripe, they fall from the gills. They are small and light enough to float for a while in the air, and the breezes help to carry them far and wide. The average mushroom may produce 2 billion spores, and the same batch of buried mycelium may produce a dozen or even a hundred mushrooms. One lucky spore may survive and become a mushroom plant that will live for more than a century.