Nutritionally they are heterotrophic, they digest food outside the body and absorb it . They are saprophytes, parasites and some are mutualistic. Their basic body plan constitutes a mass of netlike filaments called hyphae . The entire mass is called the mycelium . Most fungal hyphae are divided into cells by cross walls called septa.
Some fungi are aseptate, lacking cross walls.
They are said to be coenocytic. Some types of fungi contain lateral hyphae that absorb nutrients from other organisms, called haustoria . Reproduction is accomplished by the release of sexual or asexual spores. For many species of fungi sexual reproduction is a contingency used when environmental conditions are difficult. Under favorable conditions asexual spores are produced by the millions and dispersed over a large area.