The sterile fungi, or mycelia sterilia, are a group of fungi that do not produce any known spores, either sexual or asexual. This is considered a form group, not a taxonomic division, and is used as a matter of convenience only, as various isolates within such morphotypes could include distantly related taxa or different morphotypes of the same species,[1] leading to incorrect identifications. Because these fungi do not produce spores, it is impossible to use traditional methods of morphological comparison to classify them.[2] However, molecular techniques can be applied to determine their evolutionary history, with ITS testing being the preferred method.[1]According to one study, approximately 42% of fluids collected from broncho-alveolar lavage have had sterile mycelium observed in them.[3]