A Text-Book of Botany

A fungus is a eukaryote microbe that absorbs nutrients directly through its cell walls from the host / substrate and digests food. Most fungi reproduce sexually and by asexual spores. They have a body (thallus) composed of microscopic tubular cells called hyphae. Fungi are heterotrophs and obtain their carbon and energy from other organisms. Some fungi are parasites and obtain their food from a living host (plant or animal) and hence they are called biotrophs. Some fungi are growing as saprophytes and obtain their food from dead plants or animals. Some fungi infect a living host, but kill host cells in order to obtain their nutrients; these are called necrotrophs. Fungi were once considered to be primitive members of the plant kingdom and are slightly more advanced than bacteria. Fungi are more closely related to animals than they are to plants.