From: "Eduardo Goncalves" edggon at hotmail.com> on 2000.05.11 at 03:35:57(4566)
Dear Neil,
Unfortunately, plant taxonomy has been a guessing game most time of his
history. Opinion has been the only way to deal with the diversity.
Sometimes, you have to chose between the existence of 40 species or just a
polymorphic one. Most of the process of naming and recognizing species are
strongly subjective. The statistical (i.e. less subjective) sense of species
is somewhat far from the reality today. We are doing our best, but it is not
enough. We are using a Linnean-Aristotelic method in a Darwinian-Chaotic
world. We really don't know what is a species... We are only trained
guessers. Maybe what we call species are just communities of genes.
Sometimes genes are transferred horizontally, migrating like they was living
beings. Maybe they are the only living things around... Many natural hybrids
are exactly like "good" species, and have no clear similarity with parental
lineages. Maybe just a change in a few DNA base pairs can lead to a "new"
genus. We don't know anything about morphogenesis. We have to be humble
about our own knowledge. Probably we are living in the "middle-age" of
plant systematics, and what we call 'modern' systematics are just like
alchemy compared to modern chemistry and physics. The biodiversity wasn't
"created" to be understood. It just exists!!! The complexity usually
overwhelm our simplistic approach. It is just the beginning.
Some of you can think I don't believe in my only job. Plant taxonomy is
exactly what I do. I really believe we have to continue our work, because
alchemy is considered a silly thing today, but its contribution to physics
and chemistry was very important. We are working for future generations...
One more thing: Sometimes, floral (sexual) parts are not so useful. In
Spathicarpa, all species are almost the same in floral morphology.
Meanwhile, S. lanceolata is helophytic and have lanceolate or oblong leaves,
whereas S. hastifolia and S. gardneri have leaves that are cordate to
hastate, and the plants are always geophytes. There is only one general rule
in plant systematics: There is no general rule!!!
Best wishes,
Eduardo.
| +More |
>Where I see where you are going with this I do not beleive that "arbitrary"
>and "best guess" are how taxonomists work. Many variations do occur within
>a species concept BUT let us not get to liberal with the species concept
>over vegatative variations or color variations. What seperates ( in the
>minds of human scientists) species is sex parts......flower structure,
>spore
>structure, or cone structure. All other characters are only useful in a
>limited, circumstantial way.
>
>For example Phyllostachys nigra (Black Bamboo) was described from a
>specimen
>that only happened to have black culmns. Later (after a rare flowering
>event) it was discovered that the Type specimen (that clone which was used
>to describe the species) was actually a black culmned varient. The majority
>of the individuals of this species are green culmned like most bamboo. The
>point being that any time you look at vegetative characters instead of
>sexual characters you tread on thin ice. The sexual structures are very
>consistant (realitivly) compared to the vegatative structures of any given
>species. This consistancy is not "arbitrary" or a best guess.
>
>Actually, now that I think of it.....some taxonomists are arbitrary and
>guessers..........of course none of these are aroid taxonomists.
>
>Neil
>
>
>
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