Kingdom fungi

 The fungi constitute a unique kingdom of heterotropic eukaryotic organisms. They show great diversity in morphology and habitat.Fungi have non cellulosic cell wall made up of chitin and polysaccharides. Chitin also known as homopolymer that  form the exoskeleton of arthropods.The common mushroom and toadstools are also fungi. Some parasitic fungi cause white spot on mustard leaf also.  The number of fungi  species present on earth are more than total number  species of fishes,amphibians,reptiles and mammals. Fungi prefer warm and humid places to grow. Except yeast all fungi are filamentous. Yeast are also use in making bread and beer.Some fungi cause disease in both plant and animal,wheat rust cause by puccinia is one of the important example.Some fungi are use to make antibiotics such as penicillium.Fungi are made up of mycelium a thread like structure that has hyphae as building blocks. Hyphae without cross wall are coenocytic means multinucleate and hyphae with cross wall are single nucleate.Fungi are cosmopolitian and occur in air,water,soil and on plant and animal also.Most of the fungi are saprophytes means they absorp soluble organic matter from dead substrates and are also parasitic(depends on living plant and animal) in nature.They form symbiotic association with algae(lichens) and with root of higher plant(mycorrhiza in root of cycas).

Fungi reproduce both sexually and asexually and also by the vegetative means(fragmentation,budding and fission). Sexual spores in fungi are basidiospore,ascospore and Oospores and asexual spores are conidia,sporangiospore and zoospore. Spores are produce on special structure called fruting body.The sexual cycle in fungi includes following steps-

1.plasmogamy(fusion of protoplasm)

2.karyogamy(fusion of nucleus)

3.meiosis in zygote forming haploid spores.

In sexual reproduction two haploid hyphae come together and fuse that results in diploid(2n) cell formation.However in some cases dikaryon (n+n) condition appear and this phase called as dikaryophase. Kingdom fungi include phyckmycetes,ascomycetea,basidiomycetes and duteromycetes. Dikaryophase seen in case of ascomycetes and basidiomycetes. 

Phycomycetes 

Phycomycetes are known as algal fungi. They are found in aquatic habitats,on decaying woods,in moist and damp places and also as obligate parasites on plants. Mycelium is aseptate and coenocytic in nature.Asexual mode of reproduction performed by zoospore and aplanospore that are endogenously produce on sporangium. Sexual reproduction occur by zygospores which are formed by the fusion of two gametes.

Some common members of phycomycetes are - Rizopus,Mucor and Albugo.

Ascomycetes 

Ascomycetes are commonly known as sac fungi. They can be unicellular(yeast) or multicellular (penicillium).They also occur as saprophytes,decomposer,parates and coprophilous that growing on dung. Mycelium is branched and septate. 

Asexual reproduction occur by conidia that produce on conidiophores(a special mycelium) exogenously. Sexual spores called ascospores which are produce endogenously in a sac like asci. Some members are Aspergillous, Neurospora and Claviceps.

Basidiomycetes 

Basidiomycetes are commonly known as club fungi. They grow in soil, on log and tree stumps and in living plant body as parasite(rust and smuts). The mycelium is branched and septate type and generally asexual spores are not found. Vegetative reproduction by fragmentation is common. They don't have any sex organs but plasmogamy is carried out by the fusion of two vegetative or somatic cell of two different genotypes and the resultant dikaryotic structure ultimately give rise to basidium in which karyogamy and meiosis take place that produce four basidiospores(exogenously produce on basidium). Some  common members are- 

Agaricus, Ustilago and puccinia.

Duteromycetes 

They are called as  imperfect fungi because only asexual or vegetative mode of reproduction are known. When sexual mode of reproduction is discovered they are placed in ascomycetes or basidiomycetes. They reproduce by asexual spore conidia.

Mycelium is septate and branched. Large numbers are decomposer,while some are saprophytic or parasitic in nature. 

Some common examples are- 

Altermaria, Colletotrichum and Trichoderma.