In addition to the beauty of mushrooms, fungi are a critical part of nature's recycling system: 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. Species of many origins enjoy mushrooms.

Fungi digest food outside their bodies: they release enzymes into the surrounding environment in order to break down organic matter into a form that can be absorbed by the fungus (as well as its mycorrhizal associates).

Fungi reproduce by releasing spores from a fruiting body. The fruit, or mushroom, releases spores into the air where the wind may carry them off to start the next generation. Fungi are divided into five phyla, containing around 100,000 species, based largely on the characteristics of these reproductive organs.

Club Fungi (Basidiomycota)

When people think of mushrooms, the fruit of Basidiomycota probably comes to mind. The mushrooms in this phylum often look like umbrellas growing from the ground or shelves growing on wood, but some, such as the latticed stinkhorn pictured above, 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 either deadly, delicious, or even hallucinogenic; Boletus -- including the King Bolete (in Italy, called Porcini; in France, Cepe); and Cantherellus -- including 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.

Classes of Basidiomycota

Species in this phylum produce spores on a club-like structure called the basidium. The basidium may grow free or attached to a surface called the hymenium.

Members of the class Homobasidiomycetae produce spores on a hymenium.
Subclasses

Hymenomycetes

Those which produce spores on exposed surfaces -- releasing the spores gradually through structures such as pores or gills.
Orders: Agaricales, Aphyllophorales (3 examples)

Gasteromycetes

Those which 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.

Members of the 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).

Included in this class are Elfin Saddles (above/left), Morels, Cup Fungi, and Flask Fungi (below, left-to-right)

Another member, more famous for its side-effects than its beauty is Sacharomyces cerevisiae (Brewers, Bakers, and Nutritional Yeast) which help us produce such popular staples as beer and bread. (class: Hemiascomycetae)

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.

The mushrooms of a lichen (such as the tiny red Cladonia buttons pictured here) seems so dainty nestled in the body of the lichen.

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 - the "left-overs" that don't fit well into any of the other groups. Members include: Trichophyton (Athlete's foot), Penicillium (Penicillin), Candida albicans ("Yeast" infections).