The fungi class of Zygomycetes includes mostly terrestrial fungi. Because the hyphae have no cross walls between the cells, they are said to be coenocytic. Sexual reproduction in these organisms occurs when sexually opposite hyphae fuse and form spores called zygospores.
A common member of this class is the bread mold Rhizopus stolonifer. This fungus forms a white or gray mycelium on bread. The sporangia containing the asexual spores can be seen extending into the air. One species of Rhizopus is used to ferment rice to sake, and another species is used in the production of cortisone.