Ascomycetes

Large class of fungi (15,000 species in 1,950 genera) whose reproductive spores (ascospores) are contained in a sac-like structure known as the ascus (plural asci). It is possible to arrange the Ascomycetes in a series of groups of increasing complexity from yeastlike forms having no ascocarps (the ascus-bearing structure) to those having an elaborate macroscopic ascocarp. The largest group of ascomycete fungi are the lichens. Ascomycetes contains the Discomycetes, where the ascocarp is an apothecium, cup-shaped, and the Pyrenomycetes where the ascocarp is a perithecium, flask-shaped or rounded.