Classification of Fungi ”Biological Classification” Botany Notes Chapter 2, for Class 12-CBSE

Classification of fungi

A number of criteria are used for classifying fungi morphology of mycellum , mode of spore formation and fruiting bodies form the basis of the classification of the kingdom. A common systematic presentation is given below :

1. Oomycetes : The algal fungi
2. Hyphal wall contains cellulose and other glucans in many members.
3. The mycellum is coenocytic (multinucleate and aseptate)
4. Asexual reproduction involves the formation of spore containing sacs or sporangia. In aquatic forms, the sporangia produce zoospores.
5. Zoospores generally have two laterally inserted flagella with heterokont condition, in which one flagellum is smooth (whiplash) while the other is of tinsel type )having the surface outgrowths called mastigonemes).
6. Sexual reproduction is by planogametic fusion or gametangial contact.
7. The product of sexual reproduction and site of meiosis is oospore.

1. Zygomycetes : The conjugation fungi
2. It is class of terrestrial fungi which are mostly saprotrophic and rarely parasitic.
3. Hyphal wall contains chitin or fungal cellulose.
4. The mycelium is coenocytic (multinucleate, aseptate) like the one found in Oomycetes.
5. motile cells(zoospores or planogametes) are absent.
6. Mitospores are non motile. They are called sporangiospores as the spores are formed inside sporangia that are borne at the tips of special hyphae called sporangiophores.

6. Sexual reproduction occurs through gametangial copulation or conjugation. Because of it, zygomycetes are also called conjugation fungi.
7. the gametes are commonly multinucleate and are called coenogametes.

8.Sexual reproduction produces a resting diploid spore called zygospore. Because  of the presence of zygospore, the group of fungi is called zygomycetes. Zygospore differs from oospore in that , for its formation a distinct food laden, non motile, large female gamete is not produced.

9. Zygospore is the site of meiosis and does not give rise to new mycelium directly. Instead it produces a new sporangium called germ sporangium (previously called zygosporangium). Germ sporangium forms meiospores called germ spores.
10. Sometimes, gametangia fail to fuse. Gametangia become surrounded by a thick wall resulting in formation of azygospore(parthenogenetically produced zygospore).