Acremonium is a large, taxonomically difficult genus of unrelated wet-spored moulds. A core group of this genus is allied to the same order as the genus Stachybotrys. Several species of Acremonium occur commonly as endophytes of grasses where they produce toxic compounds believed to function as anti-feedants. However, comparably little is known about the mycotoxigenic capabilites of the majority of species of Acremonium. Many of its members are associated with soil, decaying organic construction materials as well as food products (3,5,10,13). In our experience, several species appear to be mycoparasitic (i.e. parasites of other fungi) and are often observed in association with fungus-feeding mites. We regularly report species of Acremonium from samples of outdoor air as well as water-damaged construction materials such as the cellulose layers of gypsum wallboard.