Filamentous fungi that reproduce asexually by making spores inside microscopic fruiting bodies. Estimates of the number of genera range up to 1000, with the number of species between 7000 and 10,000. They are especially numerous on living or decomposing plants, but they can occur on several other substrata. Many are plant pathogens. A few have been isolated in clinical or veterinary settings. Although all members of the group reproduce asexually by making their spores (conidia) via mitosis, some species also have known sexual states (teleomorphs) which produce spores via mating and meiosis.