Prodromus to nonlichenized, pyrenomycetous members of class Hymenoascomycetes

The orders and families of nonlichenized pyrenomycetous fungi in class Hymenoascomycetes are classified in four supraorders, based upon characteristics of the centrum and certain features of the peridium in ascomata. Morphological features of value are discussed generally and numerous variations are illustrated. A dichotomous key separates the orders.