(A) Phycomycetes- This group of fungi includes members such as Rhizopus, Albugo, etc.
(i) Mode of nutrition:
They are obligate parasites on plants or are found on decaying matter such as wood.
(ii) Mode of reproduction:
Asexual reproduction takes place through motile zoospores or non-motile aplanospores produced endogenously in a sporangium.
Sexual reproduction may be of isogamous, anisogamous, or oogamous type resulting in the formation of thick-walled zygospore.
(B) Ascomycetes- This group of fungi includes members such as Penicillium, Aspergillus, Claviceps and Neurospora.
(i) Mode of nutrition:
They are sporophytic, decomposers, parasitic or coprophilous (growing on dung).
(ii) Mode of reproduction:
Asexual reproduction occurs through asexual spores produced exogenously, such as conidia produced on conidiophores.
Sexual reproduction takes place through ascospores produced endogenously in sac-like asci and arranged inside ascocarps.
(C) Basidiomycetes- This group of fungi includes members such as Ustilago, Agaricus and Puccinia.
(i) Mode of nutrition:
They grow as decomposers in soil or on logs and tree stumps. They also occur as parasites in plants causing diseases such as rusts and smuts.
(ii) Mode of reproduction:
Asexual reproduction takes place commonly through fragmentation. Asexual spores are absent.
Sex organs are absent but sexual reproduction takes place through plasmogamy. It involves fusion of two different strains of hyphae. The resulting dikaryon gives rise to a basidium. Four basidiospores are produced inside a basidium.
(D) Deuteromycetes- This group of fungi includes members such as Alternaria, Trichoderma and Colletotrichum.
(i) Mode of nutrition:
Some members are saprophytes while others are parasites. However, a large number act as decomposers of leaf litter.
(ii) Mode of reproduction:
Asexual reproduction is the only way of reproduction in Deuteromycetes, which occurs through asexual spores called as conidia.
Sexual reproduction is absent in Deuteromycetes.