What is "leotiomyceta"

Leotiomyceta represents all the filamentous ascomycete fungi ( Pezizomycotina), excluding the classes Pezizomycetes and Orbiliomycetes. It is well supported in several studies comparing DNA sequences in fungi. It has originally been proposed as a superclass but more recently was proposed as a rankless taxon for any well supported group above class (together with saccharomyceta, dothideomyceta and sordariomyceta). Rankless taxa do not strictly follow the rules for taxonomic classifications in plants and fungi ( ICBN) and therefore these names are informal, although they appear to reflect natural groups.