The largest order of the Hyphomycetes
, containing those mycelial imperfect fungi in which the conidiophores are not compacted into specialized structures. It contains over 6000 species and some 635 genera including: Penicillium (common *moulds
), important as the source of penicillin; Aspergillus, many species of which cause spoilage of stored food, in some cases (e.g. A. flavus) producing toxic substances (aflatoxins); Botrytis and Cladosporium, common causes of leaf spot diseases; and Fusarium, one of the damping-off fungi.