A group of organisms that constitute the kingdom Fungi. Molecular studies have shown that fungi are more closely related to animals than plants, and both fungi and animals are now placed in the clade opisthokonts. Fungi can either exist as single cells or make up a multicellular body called a mycelium, which consists of filaments known as hyphae. Most fungal cells are multinucleate and have cell walls composed chiefly of chitin. Fungi exist primarily in damp situations on land and, because of the absence of chlorophyll, are either parasites or saprotrophs on other organisms. The principal criteria used in traditional classification are the nature of the spores produced and the presence or absence of cross walls within the hyphae (see ascomycota; basidiomycota; deuteromycota; glomeromycota; zygomycota). However, comparisons of ribosomal RNA sequences and other molecular studies have revealed other members of the fungi, including the Chytridiomycota, Cryptomycota, and microsporidia. See also lichens.

http://www.tolweb.org/Fungi/2377 Tree of Life survey of fungi, including phylogeny, plus many links to other sites