Classes of Ascomycota

[john taylor]

Regarding David Brayford's posting of 16 Dec 1994 that there are now no
classes of Ascomycota.

        The report on the death of fungal classes, like that of Twain, is
premature.  As we noted in 1992 (Mol. Biol. Evol. 9:278-284) there is
statistically significant support from ribosomal DNA nucleotide sequence
for two groups of Ascomycota that comprise traditional classes, i.e.,
Plectomycetes and Pyrenomycetes.  Other molecular research has supported
these classes, as well as the Hemiascomycetes, and further research is
likely to find others.  Conversely, other traditional classes of Ascomycota
have been shown not to be monophyletic, e.g., Discomycetes and
Loculoascomycetes.

        As noted by Dave Griffin, the international code is a set of rules
for nomenclature, not a listing of the outcomes of the application of these
rules.  Nothing in the rules prohibits specifying classes for Ascomycota.

        In the case of Xylaria species, it is biologically sound to include
them in the well-supported class, Pyrenomycetes (Spatafora and Blackwell,
Mycologia 85:912-922.

Mary Berbee and John Taylor.



____________________________________
From:   John Taylor
        Department of Plant Biology
        111 Koshland Hall
        University of California
        Berkeley, CA  94720
        Tel (510) 642-5366
        Fax (510) 642-4995
        internet jtaylor at violet.berkeley.edu