Coelomycetes are a form-class of fungi, part of what has often been referred to as Fungi imperfecti, Deuteromycota, or anamorphic fungi. These are conidial fungi where the conidia form in a growing cavity in the host's tissue. The fruiting structures are spherical with an opening at the apex (pycnidia) or are disc-shaped (acervuli). The formation of conidia in a fruiting body separates this group from the hyphomycetes, who have "naked" conidia.