Their club-like shape gives them the common name club fungus. Molds, Yeasts, Lichens, and Mycorrhizae A mold is a rapidly growing, asexually reproducing fungus that produces asexual spores. Later in life, the same fungus may reproduce sexually and produce zygosporangia, ascocarps, or basidiocarps. The mycelia of these fungi grow as saprobes or parasites on a great variety of substrates. An example is bread mold.
Some molds are sources of antibiotics such as penicillin.
Yeasts are unicellular fungi that inhabit liquid or moist habitats, including plant sap and animal tissues. Yeasts reproduce asexually, by simple cell division or by the pinching of small bud cells off a parent cell. Some yeasts reproduce sexually, by forming asci or basidia, and are classified as Ascomycota or Basidiomycota. Others are placed in the imperfect fungi because no sexual stages are known. Humans have used yeasts to raise bread and ferment alcoholic beverages for thousands of years.