Penecillium on an apple
The Deuteromycota or conidial fungi are a group of about 17,000 distinct species in which the sexual reproductive features are either not known or are not used to classify them. Their lack of sexual stages was the basis for them being called fungi imperfecti in the past. The term fungi imperfecti was misleading because these fungi are abundant and flourishing. Most deuteromycota have only asexual reproduction as the sexual stage of the life cycle has been lost or has yet to be discovered. There are a great number of human uses for these fungi; most significant is the production of antibiotics for medicinal use. These substances are produced by the fungus to inhibit the growth of other living organisms around them; in particular, disease-causing bacteria. These substances are extracted from the fungus and are used to kill bacteria in the human body.

Trichothecium Sp. - Conidiophore