Date: Fri, 24 Oct 1997 09:08:40 From: SCHLAUER@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg4107$foo@default> Subject: Re: VTF Classification
Dear Matt,
> I just recieved an e-mail from a girl doing a science report and I
> myself am interested. She and I would like to know the full scientific
> classification of the venus flytrap ( kingdom, Phylum, Class, Order,
> Family, Genus, Species.)
First, and most important: True Botanists will *never* buy the awkward
"Phylum" from the Zoologists (nor will there be an acceptance of the
rest of the so-called "BioCode"!). It has been Divisio, and it will
stay so as long as at least one Botanist survives. But chances are
good that this noble population of biologists will eventually be
extinguished by budget cuts, so be prepared for the worst!
Second: Forget Cronquist/Takhtajan in this corner of the plant
kingdom. The classical systems relied too much on floral morphology,
and it cannot be ignored that in this group of cps both genetical
(rbcL & rRNA) and phytochemial (acetogenic naphthoquinones) evidence
supports a classification that deviates pronouncedly from older
systems.
The division is of course Angiospermae/Magnoliophyta (flowering plants
with closed ovaries), the class is Dicotyledoneae/Magnoliopsida
s.lat. But even here, we meet the first problems. Genetical studies
have shown that there are not two monophyletic groups Monocotyledoneae
- Dicotyledoneae, but the dividing line runs through Dicotyledoneae,
some of which being more closely related to Monocotyledoneae than to
the "true" Dicotyledoneae. Most unfortunately, the smaller split-off
group includes _Magnolia_, so Magnoliopsida s.str. can only be
retained for the non-dicot group (which does not include cps), the
other (cp-containing) group has been termed "Eudicots" in the
respective slang (geneticists are not very familiar with nomenclature,
obviously; it should rather be Rosopsida or Asteropsida).
All cps belong to the "Eudicot clade" (class Rosopsida/Asteropsida)
with two cotyledons.
> The encyclopedia says that it in the sundew family, but I wasn't
> sure about this.
No need to doubt what your encyclopaedia says. It is correct,
_Dionaea muscipula_ belongs to the family Droseraceae.
The most problematic point is the order. It is a group that contains,
of course, at least Droseraceae. But it could be defined as broadly
as to contain Drosophyllaceae, Dioncophyllaceae, Anistrocladaceae,
Nepenthaceae, Plumbaginaceae, Polygonaceae, Simmondsiaceae,
Tamaricaceae, and Frankeniaceae in addition. While the tree is +/-
clear, there is absolutely no agreement between different taxonomists
which node of the tree should be identified with an order. Each of
the groups may have different names, so you can choose from
Droserales, Nepenthales, Plumbaginales, Polygonales, and Tamaricales.
This order belongs to a group that is either the sister clade of or
that belongs as a clearly defined sub-group to (subclass)
Caryophyllidae.
So we have:
kingdom Plantae/Metaphyta
division Angiospermae/Magnoliophyta
class Dicotyledoneae/Rosopsida/Asteropsida
subclass Caryophyllidae s.lat.
order ?/? (see above)
family Droseraceae
genus _Dionaea_
species _D. muscipula_.
Alternative names are separated by "/" above.
Kind regards
Jan
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