They are common and generally mild. However, in very sick or otherwise immune suppressed people, fungi can sometimes cause serious disease. Characteristics of fungi Fungi are parasites or saprophytes i.e. they live off living or dead organic matter. Mycologists identify and classify fungi according to their appearance by microscopy and in culture, and by the method of reproduction, which may be sexual or asexual. Arthrospores are made up of fragments of the hyphae, breaking off at the septae.
Yeasts form a subtype of fungus characterised by clusters of round or oval cells.
These bud out similar cells from their surface to divide and propagate. In some circumstances they form a chain of cells called a pseudomycelium. These affect the outer layers of the skin, the nails and hair. The causative organisms normally live in the soil living on rotting vegetation. They can get pricked into the skin as a result of an injury but usually stay localised at the site of implantation.