Black mould is a fungus with the Latin name Stachybotrys chartarum. It is most commonly found in buildings that have experienced water damage or are generally damp.
It consumes cellulose, meaning that it can live on things like: Wallpaper, Gypsum, drywall, paper-based products and wood; Conditions that are dark, damp, and unventilated. The less they are disturbed the better they can grow.
Black mold is very rarely found in nature, as it struggles with fluctuations in temperature, humidity, and sunlight. A home, therefore, is the perfect environment for it to grow.