Fungi are organisms with characteristics that distinguish them from both plants and animals. They constitute one of the five biological kingdoms and include yeasts, molds, rusts, mildews and mushrooms. There are four distinct classes or types of fungus, defined by their method of reproduction. The number of fungus species is unknown–one recent estimate (Microbiology Spectrum, 2017) ranges from a low of 2.2 million to a high of 3.8 million species.
To date, however, only about 150,000 species have been described. Along with bacteria, fungi serve as the planet’s cleanup, decomposition, disposal and recycling agents. They also transport and exchange nutrients with many plant species, and while it has not yet been universally accepted, there is substantial evidence that fungi may facilitate certain types of communication between plants. It is believed that fungi constitute about two percent of the earth’s biomass.
Mushrooms are the reproductive structure, or fruiting body, of a relatively small percentage of fungi. In fact, based on the species described to date, it appears that less than one percent of the fungi actually produce mushrooms. This translates into approximately 20,000 species of mushroom-producing fungi, and of that number, an estimated 300 are pathogenic to humans (causing illness or death). This is similar to the percentage of plants that are poisonous to…
