Australian Biological Resources Study
ABRS Fungi Classification Poster
Australian Biological Resources Study, 2002
Introduction |
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Fungi are very diverse. Species range from simple, single-celled organisms to very complex, multicellular organisms. The scientific classification of living organisms began in the 18th century. Then only two Kingdoms were recognised—the Plant Kingdom and the Animal Kingdom. Anything that didn't move was put in the Plant Kingdom, so that's where fungi were classified. However, fungi are very strange 'plants'. They cannot make their own food as 'ordinary' plants do through the process of photosynthesis. Now we know fungi do not belong in the Plant Kingdom. In fact, fungi are spread across three Kingdoms: Protoctista, Chromista and Eumycota. There are many levels in the classification of an organism. Kingdom is the highest level and the first step down is Division. This poster describes the major features of each Division. The Eumycota are often referred to as the 'true fungi', but the word 'fungi' is commonly used as a collective term for various Divisions from all three Kingdoms. All fungi release microscopic spores. These come in many forms, but in all cases the spores are either sexual or asexual reproductive units. Fungi in some Divisions produce mobile spores (zoospores) with filamentous asexual appendages called flagella. There are two types of flagellum: a smooth flagellum is called a whiplash flagellum; and, a flagellum where the main stem has fine, hair-like projections is a tinsel flagellum. |
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Kingdom Protoctista |
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Slime moulds (Division Myxomycota) are the only fungi in this diverse Kingdom (that includes numerous micro-organisms, but also the giant kelps). Members of the Myxomycota have a stage in the life cycle that lacks cell walls and is mobile. |
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Kingdom Chromista |
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Most members of this very diverse Kingdom are not fungi! All produce zoospores, and each zoospore has at least a tinsel flagellum. All species in this Kingdom have tubular hair-like projections on the tinsel flagellum. There are two Divisions of fungi in the Kingdom Chromista, all members of which have cellulose cell walls and are unicellular, or multicellular and filamentous. The separation of the two fungal Divisions in this Kingdom is based on the structure of the flagella on the zoospores. In the Division Oomycota the zoospores have two flagella, a posterior whiplash flagellum and an anterior tinsel flagellum. The members of the Division Hyphochytriomycota have zoospores with just one anterior tinsel flagellum. |
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Kingdom Eumycota (the true fungi) |
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Unlike the previous two Kingdoms, all members of the Eumycota are fungi. Although they vary in size and form, all species in the Eumycota have chitin in their cell walls. Chitin is the same substance that makes up insect skeletons. This Kingdom comprises five Divisions. Division Chytridiomycota has species that produce zoospores with one posterior whiplash flagellum. The Chytridiomycota are either unicellular or are made up of short (often branched) chains of cells. Species in the other four Divisions are all composed of hyphae (which are microscopically thin filaments) and do not produce zoospores. The hyphae of the Division Zygomycota have no cross-walls (or septa). The hyphae of the remaining three Divisions have septa. While the bulk of the fungi in the three kingdoms are known to produce sexual spores, using genetic material from two parents, sexual spores are unknown in the Division Fungi Anamorphici of the Eumycota. This is a 'bin' for all the Eumycota only known to produce asexual spores. The remaining two Divisions of the Eumycota are distinguished by the way they produce their sexual spores. In the Division Ascomycota the sexual spores are formed within microscopic 'pods' called asci. In the Division Basidiomycota the sexual spores are produced on microscopic cells called basidia. A basidium is often club-shaped, generally has several terminal prongs, and one spore is produced at the end of each prong.
Contact The Business Manager at abrs@environment.gov.au for your copy of the poster
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