Mary Louise Hill, age 11, of Englewood, Florida, for her question:
Why does mold form in damp places?
Damp, warm weather is moldy weather. This is when patches of blotchy mold are most likely to appear on clothes and curtains or even among the pages of our favorite books. Other moldy places are warm, moist kitchens. There the blotchy patches are likely to appear, as if by magic, on neglected scraps of food and unprotected sandwiches.
Holds and mildews belong to the plant world and all plants need moisture to keep going. Some, such as the fungus types, need more moisture than others. These mushroom and toadstool plants have no chlorophyll to manufacture their own food. They must absorb the rich nutrients manufactured by the green plants. These are found in such things as rotting wood and soils with a lot of decaying vegetation. The fungi need lots of moisture to absorb these prefabricated foods.
The molds and mildews are miniature members of the fungus family. There are dozens of different species and almost all of them are too small to be seen as individuals. T Then conditions are right, they sprout up in teeming colonies. Then we see them as blotchy patches or greens or grays, smudgy yellows or sooty blacks.
Soon the mold releases invisibly small spores that drift around in the air. Most of them finally fall onto surfaces that are too dry and perhaps too hot or too cold. But a few, a very few little spores are lucky. They fall on some warm, moist organic substance. A ripe fruit or a decaying vegetable will do just fine. So will a pile of damp clothing or a heap of steamy manure.
These things are made of prefabricated organic substances that the miniature fungi cannot manufacture for themselves. When there is warmth and moisture, a spore that just landed absorbs a rich feast thrives and grows at a great rate. In a few hours, the invisible speck becomes a visible blotch.
We often behold the beauty in nature's larger creations. But we need a microscope to see nature's artistry in invisibly small creations. To the naked eye, a patch of mold is nothing we want to admire. But when enlarged through a microscope, we can hardly believe what we see. There are numerous different molds and mildews and almost every one of them is a wondrous work of art.
Some species look like forests of feathery foliage. Others look like grassy spikes, topped with glassy round beads or graceful spires. The murky green blotch on a piece of bread may be a mold called penicillin. Magnified through a microscope, it looks like a forest of miniature stems, each topped with a fan of delicate greenery.
The fungus plants, large or small, are actually matted threads called mycelium, buried in rich damp soil or in some other suitable supply of organic food. Mold spores grow masses of matted mycelium in such things as bread. When time comes to multiply, tiny fruiting bodies pop up like mushrooms. They become visible as blurry patches. The tiny forests revealed by the microscope are stems topped with spore capsules waiting, to ripen and drift away to establish the next generation of moldy patches.