How Fungi Are Classified

How Fungi Are Classified

     There are four divisions of fungi: division Zygomycota (zygospore fungi), division Ascomycota (sac fungi), division Basidiomycota (club fungi), and division Deuteromycota (imperfect fungi).
The zygospore fungi are nonseptate, and during sexual reproduction they have a dormant stage consisting of a thick-walled zy- gospore. When the zygospore germinates, sporangia produce
windblown spores. Asexual reproduction occurs when nutrients are plentiful and again sporangia produce spores.
     The sac fungi are septate, and during sexual reproduction sac-like cells called asci produce spores. Asci are located in fruiting
bodies called ascocarps. Asexual reproduction, which is dependent
on the production of conidiospores, is more common.
     The club fungi are septate, and during sexual reproduction club-shaped structures called basidia produce spores. Basidia are lo- cated in fruiting bodies called basidiocarps. Club fungi have a prolonged dikaryotic stage, and asexual reproduction by conidiospores is rare. A dikaryotic mycelium periodically produces
fruiting bodies.
     The imperfect fungi always reproduce asexually by conidiospores; they have not been observed to reproduce sexually.
Therefore, they cannot be placed in one of the other divisions. Several imperfect fungi are of interest; for example, Penicillium is the source of penicillin, and Candida causes yeast infections.