[Taxacom] paleodicots (monosulcate dicots)

[Kenneth Kinman]

Hi Thomas,
        Although most of those other traditional characters ended up
being not so good, the dicotyledon vs. monocotyledon character has held
up very well, even when a former "monocot" group (Hydatellales) was
added to the paleodicots.         
       As for conceding to a cladistic view, that is what I was doing
when I divided dicots into 2 Classes to make it more like APG.  However,
I won't go further and split up the paleodicots (monosulcate dicots)
into multiple Classes just because it is paraphyletic.  You can only
concede to the strictly cladistic view so far before it starts becoming
counter-productive.   
       By the way, if you turn my classification upside-down and draw
lines around the three Classes, you would get that Bessyan diagram.
Class Magnoliopsida at the base, with Classes Liliopsida and Rosopsida
sticking up like two huge rabbits' ears.  The two ears would almost
touch at the base, but not quite.  Of course, the Rosopsida "ear" would
be bigger.
             ---------Ken
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Thomas G. Lammers wrote:

At 02:06 PM 2/22/2010, Kenneth Kinman wrote: >But weren't the
paleodicots always thought of as dicots >primarily 
>because of their dicotyledonous seedlings? 

Yes.  But in many of the other characters traditionally used to
distinguish the two, they fail.  There is a great deal of trimery in
flowers of these families (a supposed monocot character), despite "4's
or 5's or multiples thereof" being the dicot standard.  Some like
Piperaceae have scattered vascular bundles when the stem is viewed in
cross-section, a supposedly monocot character. 
I agree that a fundamental dichotomy is a nice thing to have.  But about
5% of our species belong to lineages whose origin pre-date that event. 
I just think its one of those places where we traditionalists can
concede to a cladistic view without really causing ourselves any
problem. 
If we were to depict phylogeny in a Besseyan fashion instead of a
Hennigian one, I could see a little blob at base (the basal lineages or
"monosulcate dicots") with two large blobs arising, the monocots and
dicots (triaperurates).