The Fungus Kingdom
(Last modified: 3 Jan 2002)
In addition to the beauty of mushrooms, fungi provide a critical part of nature's continuous rebirth: fungi recycle dead organic matter into useful nutrients. Sometimes the fungus doesn't wait for the biomatter to die, in which case the fungus is called a parasite. Many plants, however, are dependent on the help of a fungus to get their own nutrients, living in a symbiotic relationship called a mycorrhizal association. Plants aren't the only ones, however, to enjoy fungi.
Fungi digest food outside their bodies: they release enzymes into the surrounding environment, breaking down organic matter into a form the fungus can absorb. Mycorrhizal associates benefit from this by absorbing materials digested by the fungi growing among their roots.
Fungi reproduce by releasing spores from a fruiting body. The fruit, called a mushroom, releases spores into the air, and the wind carries the spores off to start the next generation. Around 100,000 species of fungi are divided into five phyla, based largely on the characteristics of their reproductive organs.
Club Fungi (Basidiomycota)
When people think of mushrooms, the fruit of Basidiomycota probably comes to mind. Many mushrooms in this phylum look like umbrellas growing from the ground or like shelves growing on wood, but some, such as the latticed stinkhorn, look quite different.
Among the more famous families in this phylum are Agaricus -- including the supermarket variety of button mushrooms; Amanita -- including species that are deadly, delicious, or even hallucinogenic; Boletus -- best known for the King Bolete (called Porcini in Italy and Cepe in France); and Cantherellus -- known for the delicious and beautiful Chanterelle. These families include but a few of the mushrooms sought by collectors and gourmets from among the 25,000 species in this phylum.
Species in this phylum produce spores on a club-like structure called the basidium. The basidium may grow free or be attached to a surface called the hymenium.
Class: Homobasidiomycetae produce spores on a hymenium.
Subclass: Hymenomycetes
Produce spores on exposed surfaces -- releasing the spores gradually through structures such as pores or gills.
Orders: Agaricales, Aphyllophorales (3 examples)
Subclass: Gasteromycetes
Produce spores on concealed surfaces, releasing spores only after the cover ruptures. Pictured below are a puffball and earthstar of the Order Lycoperdales and two stinkhorns of the Phalales Order.
Class: Heterobasidiomcetae
Produce spores on the ends of inconspicuous threads. Examples include: jelly fungi (pictured), rusts, smuts
Sac Fungi (Ascomycota)
Ascomycota produce their spores in special pods or sac-like structures called asci. Included among the 25,000 species of this phylum are the prized Morel and Truffle mushrooms (class: Euascomycetae).
Other member of this class include Elfin Saddles (above/left), Morels, Cup Fungi, and Flask Fungi (below, left-to-right)
Another class of this phylum, Hemiascomycetae, is valued more for its activity than its beauty. Sacharomyces cerevisiae (Brewers, Bakers, and Nutritional Yeast) help us produce such popular staples as beer and bread.
Other Classes: Loculoascomycetae, Laboulbeniomycetae
Lichens (Mycophycophyta)
Once the beauty of mushrooms has enticed your greater scrutiny of the forest floor, you can't help but notice lichens as well.
Lichens are a symbiotic union between fungus and algae (or sometimes photosynthesizing bacteria). The algae provide nutrients while the fungus protects them from the elements. The result is a new organism distinctly different from its component species.
Though no longer considered a proper phylum, the radically different nature of these symbiots warrants separate treatment in this overview of the fungus kingdom.
Around 25,000 species of Lichens have been identified by scientists.
Conjugation Fungi (Zygomycota)
The best known of this phylum of around 600 species is black bread mold, such as Rhizopus stolonifer.
Imperfect Fungi (Deuteromycota)
Around 25,000 additional fungus species are grouped in this phylum -- these species are the "left-overs" that don't fit well into any of the other groups. Members include Trichophyton (Athlete's foot), Penicillium (Penicillin), and Candida albicans ("Yeast" infections).
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Annotated Bibliography
Arora, David, Mushrooms Demystified (2nd edition), Ten Speed Press, Berkeley, 1986
This is the authoritative field guide to mushrooms of the Western United States. The book provides thorough keys for identifying mushrooms, as well as lively anecdotes and related information for the amateur and expert alike.
Alexopoulos, Constantine J., C. W. Mims, M. Blackwell, Introductory Mycology, (4th edition), John Wiley & Sons, New York, 1996
A college-level text on the world of fungi, organized according to the principles of classification.
Margulis, Lynn, Karlene Schwartz, Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth (2nd edition), W. H. Freeman and Company, New York, 1988
An overview of the highest levels of Taxonomy. I have used the authors' nomenclature where available. Names, however, are constantly changing in the field of Taxonomy, and no doubt many of these names are disputed or have changed since 1988.
Margulis, Lynn, Diversity of Life: The Five Kingdoms, Enslow Publishers, Inc., New Jersey, 1992
Although billed as a children's book, this book is quite appropriate for the adult amateur. Dr. Margulis strikes an excellent balance between detail and brevity in this fact-filled book.
Milani, Jean P., et. al. Biological Science: An Ecological Approach (6th edition), Kendall/Hunt Publishing Company, Iowa, 1987
A high school textbook that devotes several chapters to Taxonomy and the diversity of life on our planet. The Appendix titled A Catalog of Living Things illustrates the phyla as well as many classes and families within the five kingdoms.
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