Mould on nectarines

Mould on the ceiling of a home

Mould (or mold) is a type of fungus. It grows in the form of multicellular filaments called hyphae. In contrast, fungi that can adopt a single-celled growth habit are called yeasts.

Molds are a large group of fungi. The growth of their hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism.