This is almost certainly a paraphyletic basal radiation of ascomycetes. Some may even be more closely related to true yeasts than to pezizomycotines. Bullerwell et al. (2003). Typical members include Neolecta, the fission yeast Schizosaccharomyces, the human pathogen Pneumocystis carinii, and the plant pathogen Taphrina. As might be expected, body forms are particularly diverse among the Taphrinomycotina, ranging from relatively complex filamentous forms to single-celled yeast-like growths.
Generally, two simple body plans are found for the production of asci: uncovered asci with unicellular growth, or a rudimentary ascocarp with hyphal growth. That is, these fungi grow either unicellularly or with a sparse mycelium, and their sexual phase normally produces naked asci directly from the ascogenous cells. Only Neolecta produces a (primitive) enclosing ascocarp. Liu & Hall (2004).