Give a brief account of the various systems that have been suggested to classify fungi.

Ans. The first attempt to classify and describe the fungi was made by Persoon (1801). He published the “Synopsis Methodica Fungorum” which is regarded as the starting point of the nomenclature of the Rusts, Smuts and Gasteromycetes. Persoon arranged the species into Classes, Orders and Families. Between 1821 and 1829, Elias Fries completed the “Systema Mycologicum” and gave a full account of all the fungi known by that time.

In 1937, Leveille recognized the Ascomycetes and asidiomycetes as two main groups. De Bary (1866) in the “The Comparative Morphology and Biology of the Fungi” presented many new observations such as the discovery of heteroecism and recognition of Phycomycetes as a distinct class.

There are various systems of classifications, some disagree on basic principles, whereas many of them differ in detail. Eichler (1886) gave a more conservative system of classification and divided the primitive Division Thallophyta into two Classes (see table below): Algae and Fungi. The fungi comprised to Schizomycetes, Eumycetes and Lichens.

This system was discarded as it provided an incorrect impression that the three groups represent a direct line of evolution. character of

Goebel (1887) divided the Fungi, according to the vegetative organs, into three classes as follows:

(1) Fission Fungi (Bacteria)

(2) Sprouting Fungi (Yeasts)

(3) Spawn Fungi (includes all fungi with hyphal growth). In 1890 Zopf gave an account of the lower phycomycetes in his “Die Pilze”. Patonillard (1900) classified higher basidiomycetes on hymenial characters.

Burnett (1968) gave a very broad outline classification of Fungi without explaining the basis of separation of different taxonomic categories.

Class  – Phycomycetes

Subclass – Plasmodiophoromycetes

Subclass – Hyphochytridiomycetes

Subclass – Chytridiomycetes

Subclass – Oomycetes

Subclass – Zygomycetes

Subclass – Trichomycetes

Class – Ascomycetes

Series – Hemiascomycetidae

Series – Euascomycetidae

Plectomycetes

Pyrenomycetes

Discomycetes

Laboulbeniomycetes

Series – Loculoascomycetidae

Class – Deuteromycetes

Class – Basidiomycetes

Series – Heterobasidiomycetidae

Series – Homobasidiomycetidae

Hymenomycetes

Gasteromycetes

Again Talbot (1969) subdivided Fungi and Fungus-like organisms as follows:

Fungi with a plasmodial thallus Division Myxomycota (Slime Molds) Non-colonial slime molds

Sporangiate fructification present, not endoparasites

Class Myxomycetes

Sporangiate fructification lacking, endoparasites

Class Plasmodiophoromycetes

Colonial slime molds

Net slime molds, mostly parasitic on marine plants

Order Labyrinthulales

Order Acrasiales

Cellular slime molds, saprobes

Fungi with a non-plasmodial thallus Division Eumycota (True Fungi)

Thallus unicellular uninucleate, poorly to well-developed aseptate mycelium with a tendency to develop septa; asexual pores motile or nonmotile sporangiospores; sexual reproduction results in the formation of oospores or zygospores; absence of fruit bodies

Sporangia with zoospores, predominantly oogamous

Subdivision Mastigomycotina

Sporangia with aplanospores, entirely zygogamous

Subdivision Zygomycotina

Members of the Subdivisions: Mastigomycotina and Zygomycotina, together formerly known as ‘Phycomycetes’, include what are usually thought

to be the most primitive types of Eumycota, even though the simplest show much diversity of form and complexity of life  cycle.

Thallus with septate mycelium; asexual spores other than sporangiospores; sexual reproduction results in the formation of asciand ascospores or basidia and basidiospores usually in fruit bodies.

Presence of asci and ascospores

Subdivision Ascomycotina

Presence of basidia and basidiospores

Subdivision Basidiomycotina

Thallus structure and asexual spores are similar to Ascomycotina and Basidiomycotina; sexual reproduction lacking

Subdivision Deuteromycotina

Webster (1970) adopted a scheme of classification of Fungi and Funguslike organisms proposed by Ainsworth (1966) which is briefly outlined below:

Division Myxomycota

Class Acrasiomycetes

Class Hydromyxomycetes

Class Myxomycetes

Class Plasmodiophoromycetes

Division Eumycota

Subdivision Mastigomycotina

Class Chytridiomycetes

Class Hyphochytridiomycetes

Class Oomycetes

Subdivision Zygomycotina.

Class Zygomycetes

Class Trichomycetes

Subdivision Ascomycotina. (Ascomycetes)

Class Hemiascomycetes

Class Plectomycetes

Class Pyrenomycetes

Class Discomycetes

Class Laboulbeniomycetes

Class Loculoascomycetes

Subdivision Basidiomycotina (Basidiomycetes)

Class Hemibasidiomycetes

Class Hymenomycetes

Class Gasteromycetes

Subdivision Deuteromycotina (Fungi Imperfecti)

Class Coelomycetes

Class Hyphomycetes

Class Agonomycetes

Elizabeth-Moore-Landecker (1972) classified Fungi separately for lower fungi and higher fungi.

Classification of lower fungi based on flagellation was adopted from Sparrow (1958).

Uniflagellates

Class Chytridiomycetes

Class Hyphochytridiomycetes

Biflagellates

Class Plasmodiophoromycetes

Class Oomycetes.

Non-flagellates

Class Zygomycetes

Classification of the Ascomycetes was based on gross morphology, anatomy, and life history of the individual organisms.

Class Ascomycetes

Subclass Hemiascomycetidae

Subclass Euascomycetidae

Series Bitunicatae

Series Unitunicatae

Subseries Loculomycetes

Subseries Plectomycetes

Subseries Pyrenomycetes

Subseries Discomycetes

Subclass Laboulbeniomycetidae

Classification of the Basidiomycetes was based on the morphology of the basidium.

Class Basidiomycetes

Subclass Heterobasidiomycetidae

Subclass Homobasidiomycetidae

Series Hymenomycetes

Series Gasteromycetes

The Fungi Imperfecti: The members of the Fungi Imperfecti were combined in a single group because they apparently lack a sexual cycle and there was no convenient place in the remainder of the fungus classification system, which is based principally on the mode of sexual reproduction.

Whether the Myxomycotina are closely related to the Eumycota (True Fungi) is yet to be decided. There is a possibility that they are closely related to Protozoa.

Again the somatic phase of the Plasmodiophoromycetes is so different from that of the true fungi with which they are often classified based on the nature of flagellate cells.

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