Active mold can be any color, depending on the species and the substrate upon which it is growing. Mildew is another type of fungus, similar in structure to mold, but distinct as one species of fungus is distinct from another. Fungi is a kingdom of organisms, with a single division, Mycota. The fungi have traditionally been classified with plants but are now considered a distinct group of organisms. Unlike plants, which produce their own food, fungi absorb nutrients from dead or living organic matter.
Fungi also lack photosynthetic pigments.
There are over 100,000 known living species of fungus, some of which are beneficial to mankind. Mycologists estimate that there may be as many as 200,000 more unidentified species of fungus. The spores of fungi that become mold or mildew are always present in the air and on objects. When the temperature and moisture in the environment are suitable for germination, the fungus spore bursts and grows into a thread-like filament called a hyphae. Using the object it is growing on as a food source, the hyphae form a mass, called a mycelium, and within a short time begin to produce spores.