Zygomycetes is not the name of particular fungus, but rather the name of a Class of fungi. This Class includes three Orders (Mucorales, Mortierellales, and Entomophthorales). These Orders in turn contain a number of specific fungi (see table below).
Nomenclature debate: Zygomycosis vs. mucormycosis.
The diseases produced by these fungi are referred to by the label zygomycosis. Of note, some literature also refers to these diseases by the name mucormycosis, but this terminology has generally fallen from favor for two reasons. First, Mucor spp. are only rarely the cause of zygomycosis (Rhizopus spp. are the most common cause). Second, the term mucormycosis could be taken to imply that only the Mucorales cause zygomycosis. Although the Entomophthorales can produce some relatively distinct syndromes, they can also cause disease indistinguishable from classical zygomycosis. Thus, we use the term zygomycosis in preference to mucormycosis to describe disease due to fungi of this type.