Black bread mold, several insect parasites, and a few predaceous soil fungi are included in this group. Vegetative growth results in the production of mats of haploid filaments that lack photosynthetic pigments. The filaments lack cross-walls and are therefore called "non-septate." Filaments that penetrate a substrate (e.g., bread or dung) are called rhizoids. Those that run along the surface are called stolons. Asexual reproduction is facilitated by filaments that rise above the surface. Non-flagellated spores are produced by mitosis in a swollen terminal tip (Fig.1 or Fig.2). The swollen tip is separated from the rest of the upright filament by crosswall. Spores are passively released into the air or are actively discharged in some species. If they land on a suitable substrate they produce new haploid filaments.

Sexual reproduction occurs when filaments of two different strains come into close contact. Each produces a short lateral branch. When the branches touch, crosswalls form so that each branch becomes a multinucleate gametangia. The walls between touching branches break down, creating a multinucleate zygote (Fig.3). Nuclei from each strain pair and fuse. The zygote cell develops a thick, warty wall and becomes dormant. Meioses occur when a zygote germinates. Non-flagellated meiospores grow into new haploid filaments to complete the sexual cycle.

Because of the lack of a fossil record, the phylogenetic origin of zygomycetes is uncertain. It is a relatively small group of about 350 species, but is also one of the most commonly encountered groups of fungi from soil isolates.