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A class of terrestrial fungi in the phylum Zygomycota, comprising organisms commonly known as the bread molds. Sexual reproduction is by the formation of zygospores. Asexual reproduction is by endospores (sporangiospores) produced in sporangia, or uni- or multispored sporangiola or merosporangia, conidia, yeast cells, chlamydospores, or arthrospores. These fungi occur as haustorial (having food-absorbing cells in the host) or nonhaustorial parasites of fungi, plants, or animals (including humans), or as saprobes, especially in soil or dung; but other substrates with soluble nutrients may also contain Zygomycetes. Some taxa are endo- or ectomycorrhizal on vascular plants.
The mature spore-bearing structures are dry and readily dispersed by air currents, or are wet and are distributed by direct contact with small animals or are ingested by animals and disseminated in their feces. Water droplets also may disperse the spores or the intact spore-bearing structures.
Classification is based on mode of nutrition, morphology of the zygospore (if formed), type of asexual reproduction, branching pattern of sporophores, and frequency of septa (if formed) and septal morphology. Zygomycetes are currently placed in seven orders: Dimargaritales, Endogonales, Entomophthorales, Glomales, Kickxellales, Mucorales, and Zoopagales. Zygomycetes are distributed worldwide, although many taxa are rarely encountered; they may be relatively common on a particular host or substrate. See Eumycota, Fungi
a subclass of lower fungi of the class Phycomycetes. The mycelium is well developed and is usu-ally not divided into individual cells by transverse septa, except for the reproductive organs, which are often separated by septa. Zygomycetes reproduce by a sexual process of zygogamy and asexually by means of nonmotile sporangiospores that develop in sporangia, which are elevated above the mycelium on sporangiophores. In many Zygomycetes there is a transition to reproduction by means of conidia. Zygomycetes are divided into several orders, the most common of which are Mucorales and Entomophthorales. Some mycologists include the little-studied fungus orders Zoopagales and Eccrinales in the Zygomycetes.