Introduction to Fungi, Third Edition

CLASSIFICATION
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These taxonomic groups are broadly
supported by phylogenetic analyses (Swann &
Taylor, 1993). An example of the kind of arrangement
currently proposed for the basidiomycetes
is shown in Fig. 18.21. Because their basidia are
arranged on a freely exposed hymenium, the
Heterobasidiomycetes and Homobasidiomycetes
are sometimes collectively termed Hymenomycetes.
Various basidiomycetes in which the
hymenium is not freely exposed and which do
not discharge their basidiospores violently have
adopted alternative methods of spore dispersal.
They are related to a number of Homobasidiomycete
groups, from which they have arisen in
the course of evolution. Whilst recognizing that
they do not form a natural group, they are here
considered together as gasteromycetes because
they share important biological features (see
Chapter 20). Basidiomycetous yeasts are another
artificial assemblage of fungi which have relationships
with various taxonomic groups; these
are also considered in a separate chapter
(Chapter 24).