RE: var., ssp., forma.

Michael.Chamberland (23274MJC@MSU.EDU)
Mon, 30 Jan 95 20:47 EST

> >I've just read Barry's piece on correct plant names, and it is very
> helpful,
> >at least to me. However, it leaves open one question that I
> occasionally
> >think about: What's the difference between 'var,' 'ssp,' and 'f'? Is
> this
> korfhage@lis.pitt.edu
> >
> >
>
> I am involved with a lot of different plant groups and I have hung out
> with a lot of plant taxonimists. You would get two different answers
> from the two main classes of taxonomists.
> The Lumper: He instantly discards any thing like subspecies, variety or
> forma. He subscribes to the broad species concept.
> The Splitter: He loves to publish and see his (her) name in Index

I beg to differ here. Firstly, the issue of lumping and splitting has
little to do with the distinction of varieties (var.), subspecies (ssp.),
or forms (f.).
The splitter places a greater weight on variation within a group, and so
recognizes more taxa (different named units) within that group. The lumper
chooses to place a greater emphasis on the similarities that exist in spite
of variation, and in so doing recognizes fewer taxa within a group.
A splitter may recognize ten species within a genus, while a lumper may
recognize only five species within that same genus. They need not designate
infraspecific taxa (var., ssp., f.) in their treatments of the genus.
Neither lumping nor splitting is "bad". However, any proposed changes in
nomenclature should be substantiated with documented reasons for doing so,
not just because the reviewer "felt like it" or wanted to author a new
taxon.

> Kewensis. According to him, a subspecies different enough from the main
> species to deserve recognition, but not enough to merit a new species.
> This new subspecies will generally be based upon GEOGRAPHIC SEPERATION
> from the main species. The variety ranks below subspecies and is
> generally applied to size 'Maxima' or color 'Rubra'. (P.S. As a lumper,
> this is as stupid as calling a Negro Human: Homo sapien var. Nigrum or a
> genetic dwarf Homo sapien 'minima' Genetic varieation in color, size or
> even minor physical traits does not make for a new species) 'Forma' is
> along the same lines, and was in vogue many years ago.

The variety, subspecies, and form are infraspecific taxa. That is,
taxonomic divisions below that of species. The species is generally
considered to be the most important evolutionary unit within the taxonomic
hierarchy, and also the most redily recognized unit by both modern and
culturally primitive people (though ramifications of the species concept
are hotly debated). All genera have at least one species. Not all
species have been divided into infraspecific taxa.

In the taxonomic hierarchy, subspecies is a higher level than variety, however
these two categories have NOT been used consistently by botanists. For
practical purposes you can usually consider var. to be synonomous to ssp.
although the two should not be used interchangeably. Both descriptors
refer to morphological variation usually involving several charactors and
having a geographical basis. Hybridization is commonly found between
different ssp. or vars. of a species. Natural hybridization may blur the
distinction between varieties of a species (or subspecies of a species)
and this is one of the most common reasons why these taxa are not raised to
the level of distinct species.

Whenever an infraspecific taxon is designated in a species, TWO infraspecific
taxa are automatically created. For example, when Macfar. (J. M.
Macfarlaine)?investigated Drosera filiformis, he considered the species to
consist of two different "kinds" of plants, one he described as D. filiformis
var. tracyi.This automatically created D. filiformis var. filiformis, the
"other" kind of D. filiformis. This name is called the autonym, and is
automatically created. Because the type specimen of D. filiformis was not of
the "tracyi" kind, it became the autonym or "nominal variety" when the "new"
variety, v. tracyi, was described.

The category form is used to describe variation which does not have a
geographical basis, and which is usually sporadic in a population.
Anthocycanin-lacking individuals occur infrequently in plant populations
and have sometimes been formally recognized as forms. However, the use of
form is often discouraged, except for extremely unusual variants, or forms
which occur in economically important plant groups. As Barry has pointed
out, variation can be described in other ways than formal designation of
forms.

(I am not sure about the creation of autonyms when forms are designated).

> BTW...God never made a species or a subspecies. Man decides what is or
> isn't a species and a published species isn't a given it's only one
> persons opinion, open to debate.

Taxonomists believe that God (or more properly, evolution) DID create
species (as well as infraspecific variation) which we HOPE are adequately
described by our taxonomic descriptions :-)

Michael