Oomycetes:
– they are fungi that produce oospore (egg)
– cause several parasitic disease of plant, fish, insect and human
– some are saprophytes or weak parasites
– most develop mycelia of indefinite form
– Actively growing haphae
– cross walls separate reproductive from vegetative hyphae
– Asexual reproduction occurs in the presence of ample food supply
– occur by formation of spores in sporangia
– sexual reproduction (gametangial copulation) by oogonia and antheridia
– the class is divided into two order: saprolegniales (saprolegniasp) and perenosporale (perenospora, phytophthora sp.)
Zygomycetes:
– they do not have motile cells
– produce resting spore called zygospore
– mainly terrestrial
– extensive coenocytic mycelia
– mycelia contain chitin
– sexual reproduction by conjugation
– Union of two mating types
– asexual reproduction by sporangia
– mostly saprophytic, few are parasitic
– e.g. rhizopus, mucor
– produce sexual spores in asci
– cell wall contain chitin
– septate mycelia/cross-wall in mycelia which allow passage of organelles
– sexual reproduction involve fusion of ascogonia and antheridia/spermatia
– ascogenous hypha (dikaryon) produce asci by hook/crozier method
– asci is usually concentrated in a fruiting body
– fruiting body is called ascocarp
– fruiting body contain both vegetative and reproductive hyphae
– characteristic of species
Three main types: apothecium, perithecium and cleistothecium
– asexual reproduction by conidiophores bearing asexual spores; conidia
– e.g yeaster, erysiphe, moulinia
Basidiomycetes:
– most advanced group of fungi
– some produce elaborate fruiting bodies called basidiocarp (homobasidiomycetes)
– others do not (heterobasidiomycetes)
– sexual meiospores (basidiospores) are borne on individual stalks called sterigmata
– homobasidiomycetes  are mostly saprophytic, e.g mushrooms, puffballs, bracket fungi, some are parasitic, others are symbiotic
– include rusts (Puccinia, ustilaga) of crops
– fungi imperfecti. The imperfect fungi which are known only by their asexual stages
– encompasses fungi. Which may belong to ascomycetes and basidiomycetes.
– one from order is wide spread
– contain common genera like penicillin and aspergilus
– both form conidia which are widespread in air, soil and water.