Fungi are the dominant saprophytes of terrestrial ecosystems. The hyphae secrete enzymes which desolve the dead organic material which is then absorbed by the hyphae. Not all fungi are saprophytes, however. Some fungi, apparently impatient for plants and animals to die, have become parasites. Atheletes Foot is one such parastic fungus.
Many fungus are pathogens of plants.
In contrast many species of fungi have formed symbiotic relationshps. Lichens are a symbiotic relationship with green or blue-green algae, the fungus providing the structural part of the combined organism and the algal component performing the photosynthic duties. Several fungal species have symbiotic relationships with plants which are explored in some of the links given in these fungal pages. The fungi are now considered to belong to four groups, one of which is artificial. These four groups are distinguished by the form of their reproductive structures.