The Growing Fungus

Abstract

Unlike the ‘higher fungi’ described in later chapters the ‘lower fungi’ are a very diverse and polyphyletic assemblage of organisms. Ultrastructural ( CR76 1986 ; CR11, 1987 ; CR3, 1992 ; CR86, 1994 ) and molecular studies ( CR24 et al, 1992 ) reveal that many of the zoosporic groups within the ‘lower fungi’ (Oomycetes, Plasmodiophorales, Thraustochytriales) show closer evolutionary affinities with the protists and chromophyte algae than they do with most other fungi. The uniflagellate Chytridiomycetes appear to be on the same evolutionary line as the terrestrial fungi, including the non-motile Zygomycetes. Because of shared morphological similarities (e.g. nonseptate hyphae and the production of sporangiospores), the latter have traditionally been grouped in the lower fungi.