SUBJECT: Fungal classification
DATE: 5/97
 
(This discussion grew out of a thread on classifying bacteria)
 
In a message dated 5/14/97 9:54:50 AM, Liane Cochran-Stafira wrote:
 
>Yikes, even the fungi are a mess
 
Depends on what you mean by fungi. The Kingdom Fungi itself is fairly well
circumscribed (though difficult to convey to beginning students). It's the
protist "fungi" (water molds, slime molds, chytrids, etc.) that are the
problem.
 
Dave Williams
Science Division
Anne Arundel Community College
Arnold, MD 21012
Vmail: 410-541-2265
Email: profdhw@aol.com
 
 
Sounds like "the fungi are a mess" since it "Depends on what you mean by
fungi," and some organisms are problematic members - such as the
"protist 'fungi'".
 
Dave McNeely
 
 
That's just it, Dave. The protist "fungi" are not members of the fungi except
in a loose sense, like that in which some vascular plants and algae are
called mosses. In this use the designation "fungus" is more like a habit,
comparable to "tree" or "vine". There is no current taxonomic place for these
fungus-like protists but the Kingdom Protista, yet most are quite different
from the traditional protozoa and the many kinds of eukaryotic algae. The
water molds, slime molds, and chytrids, that is, the "protist fungi"--as
distinct groups--are clearly defined (and not a mess). They are about as much
fungi as the protozoa are animals. Did anybody say the animals were a mess?
 
My point was that the Kingdom Fungi (zygomycetes, basidiomycetes,
ascomycetes--the genuine fungi) is not a mess at all. It is very clearly
defined if a bit small and difficult to explain to the uninitiated. It is the
most genetically circumscribed and pedagogically rewarding Kingdom of the
five. Even if you lump the Kingdom Fungi, water molds, slime molds, and
chytrids together as fungi (in the loose sense) you are in no more difficulty
than when you cover the protozoa with the "animals".
 
May I repeat: THE FUNGI ARE NOT A MESS.
 
Dave Williams
Fungus Lover
Anne Arundel Community College
Arnold, MD 21012
Vmail: 410-541-2265
Email: profdhw@aol.com
 
 
Fungi are cool, but what about the Deuteromycetes? Now they're a
mess!
 
John Dickerman
Northern Illinois University
T80JWD1@WPO.CSO.NIU.EDU
 
 
 
In a message dated 5/15/97 10:39:11 AM, John Dickerman wrote:
 
>Fungi are cool, but what about the Deuteromycetes? Now they're a
>mess!
 
Not really. The vast majority are simply ascomycetes with no sexual stage yet
observed. Most of the deuteromycetes are well studied as "industrial fungi"
because of the economic effect of their growth on food or other organic
products.
 
The deuteromycetes are members of a form category--one established to hold
taxa until they can be properly assigned. The problem is that it is not
possible to positively identify an asexual stage as an ascomycete or a
basidiomycete (not so with the zygomycetes, they all have aseptate hyphae).
The only difference is in the sexual stage--ascus vs. basidium. With no
sexual stage they must be put in a "holding facility" until such time as the
sexual stage is observed. Pedagogically this is hardly a problem. The only
useful deuteromycetes are in the form genera Penicillium and Aspergillus, all
species of which eventually show up as ascomycetes.
 
Form categories (typically genera and species) are common in fossil plants as
well. When isolated leaves are found in the sedimentary layers there is no
choice but to assign them to a form species until the paleobotanist can
connect them to the proper stems, cones, seeds, etc.
 
There are instances in paleobotany of form genera persisting in the record
for years until a fortuitous discovery of an ideal fossil--say, a leaf in one
form genus actually connected to a stem of a different form genus--that the
several genera are united into a single connected species.
 
The truly messy aspect of the fungi is the taxonomic naming of the
categories. That's why we keep referring to the ascomycetes, basidomycetes,
and so forth, without using any actual phylum or class names. The fungus
taxonomists cannot agree on what to call them and at what level the various
groups should be held. In my opinion this is the result of the persistent
influence of many "old line" mycologists who refuse to enter the modern era.
 
By the way, according to the Tree of Life web site the chytrids are now
classified into the Kingdom Fungi. Progress I suppose (how reluctant we are
to abandon our old beliefs). The evidence seems to be mainly molecular and
fairly conclusive.
 
Dave Williams
Science Division
Anne Arundel Community College
Arnold, MD 21012
Vmail: 410-541-2265
Email: profdhw@aol.com
 
 
 
I object to the exclusion of the Mastigomycetes (water molds) from the "real
fungi". Put the Gymnomycota (slime molds) in with the Protists if you want -
they are phagotropic -and nutrition is the name of the game. But leave the
water molds alone - they are all just as absorptive as the Amastigomycetes.
Just because they have "sex on the go" with flagella and are a bit more
primative they are as real as any basidiomycete you might meet in the woods.
Most of this planet is covered in water and that's where the water molds are
- just because we're stuck on dry land that doesn't make the fungi stuck with
us "real".
 
Leslie Lichtenstein
Massasoit Community College
leslichten@AOL.com
 
 
Leslie:
 
Nutritional modes and locomotive appendages are not the only criteria for
classification. The water molds have clear affinities to the brown algae and
other groups not at all capable of being classified in the Kingdom Fungi. As
I attempted to explain, the designation "fungus" is more like a habit, not a
meaningful taxonomic designation. Have you tried the Tree of Life website?
 
http://phylogeny.arizona.edu/tree/phylogeny.html
 
There is also a great fungus page at:
 
http://phylogeny.arizona.edu/tree/eukaryotes/fungi/fungi.html
 
The chytrids (an odd but very interesting group of protists usually lumped
with water molds) have recently been included with the "real" fungi. They do
have undulopodia. The exclusion of the other "water molds" from the Kingdom
Fungi does not make them less real. It does make them deserving, perhaps, of
their own kingdom (together with the brown algae and some other protist
groups).
 
My implication that some fungi are "real" was not an attempt to denigrate the
importance of any life form. It was just a jocular turn of phrase. I went to
school with a zoologist who, when faced with a seminar on mosquitoes, implied
that only mammals were "real" animals (again in a jocular mode). No one, not
even the mosquito man, got upset. We all chuckled and went on with the
seminar.
 
Dave
 
Dave Williams
Science Division
Anne Arundel Community College
Arnold, MD 21012
Vmail: 410-541-2265
Email: profdhw@aol.com
 
 
 
In regard to the Deuteromycetes being a form taxon, Dave Williams wrote:
 
Form categories (typically genera and species) are common in fossil plants as
well. When isolated leaves are found in the sedimentary layers there is no
choice but to assign them to a form species until the paleobotanist can
connect them to the proper stems, cones, seeds, etc.
 
There are instances in paleobotany of form genera persisting in the record
for years until a fortuitous discovery of an ideal fossil--say, a leaf in one
form genus actually connected to a stem of a different form genus--that the
several genera are united into a single connected species.
 
-----------------------------
 
I just want to add that in many cases, after several form taxa (of fossil
plants) are found connected and treated as a real species, the form taxa are
maintained in the literature. This is done because of the likelyhood that
different species made the similar structures that we cannot distinguish. Thus
we have plants that are made of several differently named parts and individually
named parts that came from several different plants. Carboniferous arborescent
lycopsids are a great example of this.
 
Doug Jensen
Berea college
 

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