Key concepts:
Many fungi are opportunistic heterotrophs, disposers of, or recyclers of, organic substrates, especially those of plant origin.
Parasitic fungi attack almost all known taxa of plants and animals.
Fungi have established mutualistic symbioses with cyanobacteria and chlorophycota (green algae) to form lichens.
Fungi often form symbiotic associations with the roots of plants (bryophytes, pteridophytes, gymnosperms and angiosperms) in mycorrhizae.
Some fungi live as symbionts with coleoptera, diptera, homoptera and hymenoptera.
Some fungi cause diseases (mycoses) in humans or excrete toxic compounds (mycotoxins).
Fungal spores can cause severe allergies in humans.