Kingdom Fungi

A Scientific Classification of Earth's Fungal Diversity

Understanding Fungal Taxonomy

The Kingdom Fungi comprises over 144,000 described species with estimates ranging from 2.2 to 3.8 million total species. Fungi are neither plants nor animals but represent a unique kingdom of life essential to virtually all terrestrial ecosystems. They decompose organic matter, form symbiotic relationships with plants, produce foods and medicines, and shape the very soil beneath our feet.

This classification system organizes fungi into major phyla (divisions) based on their reproductive structures, life cycles, and evolutionary relationships. Modern molecular phylogenetics continues to refine our understanding of fungal relationships, revealing surprising connections and driving taxonomic reorganization.

Major Fungal Phyla

Explore the eight major divisions of the fungal kingdom, from familiar mushrooms to microscopic parasites.

Basidiomycota

Club Fungi

Basidiomycota, commonly known as club fungi, represents the most familiar group of fungi to most people. This diverse phylum includes mushrooms, puffballs, stinkhorns, bracket fungi, rusts, and smuts....

Estimated Species 30,000+ described, potentially 1.5 million total

Examples: Button Mushroom, Fly Agaric, Oyster Mushroom

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Ascomycota

Sac Fungi

Ascomycota, the sac fungi, is the largest phylum of fungi with extraordinary diversity in form and lifestyle. Members range from unicellular yeasts to complex cup fungi, morels, and truffles. The defi...

Estimated Species 64,000+ described, potentially 1-3 million total

Examples: Common Morel, Black Truffle, Penicillium Mold

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Zygomycota (paraphyletic)

Conjugated Fungi

Zygomycota (now recognized as paraphyletic and divided into Mucoromycota and Zoopagomycota) represents an ancient lineage of fungi, primarily known as bread molds and soil fungi. These organisms are c...

Estimated Species 1,000-1,500 in traditional grouping, taxonomy under revision

Examples: Black Bread Mold, Common Mucor, Dung Cannon

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Chytridiomycota

Chytrids

Chytridiomycota represents the earliest-diverging lineage of fungi, often considered the most primitive fungi. Unique among fungi, chytrids produce motile zoospores with a single posterior flagellum. ...

Estimated Species 1,000+ described, potentially 5,000-10,000 total

Examples: Bd, Water Mold (historic misnomer), Potato Wart

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Glomeromycota

Arbuscular Mycorrhizal Fungi

Glomeromycota comprises fungi that form arbuscular mycorrhizae (AM), one of the most widespread and ancient symbiotic relationships on Earth. These fungi colonize the roots of approximately 80% of pla...

Estimated Species 300-350 described, potentially 1,000+ including cryptic species

Examples: AMF, AM Fungus, Giant-spored AM Fungus

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Blastocladiomycota

Blastoclad Fungi

Blastocladiomycota is a small phylum of primarily aquatic fungi, formerly classified within Chytridiomycota but now recognized as a distinct lineage. Like chytrids, they produce flagellated zoospores,...

Estimated Species ~180 described species

Examples:

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Neocallimastigomycota

Anaerobic Gut Fungi

Neocallimastigomycota comprises a unique group of obligately anaerobic fungi found exclusively in the digestive tracts of herbivorous mammals. These fungi are remarkable for surviving and thriving in ...

Estimated Species ~20 described, potentially 100+ including undiscovered species

Examples: Gut Fungus, Anaerobic Gut Fungus, Polyflagellate Gut Fungus

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Microsporidia

Microsporidia are highly specialized obligate intracellular parasites, once thought to be protists but now recognized as highly derived fungi. These minute organisms (1-40 μm) infect virtually all ani...

Estimated Species 1,500+ described, potentially 10,000-100,000 total

Examples: Honeybee Microsporidian, Human Microsporidian, Rabbit Microsporidian

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