any fungus of the phylum Ascomycota (formerly class Ascomycetes) in which the spores (ascospores) are formed inside a club-shaped cell (ascus). The group includes yeast, penicillium, aspergillus, truffles, and certain mildews
Any of various fungi belonging to the phylum Ascomycota, characterized by the presence of sexually produced spores formed within an ascus. Like most fungi, ascomycetes also reproduce asexually by the formation of nonsexual spores called conidia at the ends of filaments known as hyphae. Yeasts, many molds that cause food spoilage, and the edible fungi known as morels and truffles, are ascomycetes. A number of serious plant diseases, including ergot, the powdery mildews that attack fruit, and Dutch elm disease, are also caused by ascomycetes.