Ascomycota is a Division/Phylum of Fungi, an subkingdom Dikarya, whose members are commonly known as the Sac Fungi. Characteristically, when reproducing sexually, they produce nonmotile spores in a distinctive type of microscopic cell called an "ascus" (from Greek: ἀσκός (askos), meaning "sac" or "wineskin"). These spores are called ascospores. However, some members of the Ascomycota do not reproduce sexually and do not form asci or ascospores. These members are assigned to Ascomycota based upon morphological and/or physiological similarities to ascus-bearing taxa, and in particular by phylogenetic comparisons of DNA sequences.