Phylum Pteridophyta (classification modified)

Ken Kinman kinman2 at YAHOO.COM
Sun Mar 13 12:56:55 CST 2005

Dear All,
      I suspect that I have seen instances of equating Pteridophyta with the "true fern" clade, but I probably thought it was just a dumb mistake (for Pterophyta).  Now I am informed this cladification happened decades ago (apparently at the University of Michigan), and Curtis seems to think this cladistic hijacking of the name is fine and dandy and widely accepted.  On the contrary, the vast majority of botanists (even many who teach systematics), still refer to seedless tracheophytes as Pteridophyta (or informally as "pteridophytes" if they feel a strict cladist breathing down their neck).  And they accuse US of trying to deny THEM the tools they need?

     There is absolutely no excuse whatsoever for applying the name Pteridophyta to the fern clade.  That clade has plenty of other names as it is (Filicophyta, Pterophyta, Polypodiophyta, plus the class equivalents with -opsida endings).  I once prefered Pteropsida or Pterophyta for the true ferns, but in view of this further confusion, I am now switching to Filicopsida (as in the Tree of Life, which thankfully just avoided using Pteridophyta).  The classes of bryophytes remain the same as in 1994, but I'm putting them in for context.  I see no reason to abandon the four phyla of Kingdom Metaphyta (although some might prefer the names Gymnospermae and Angiospermae, rather than Pinophyta and Magnoliophyta).


 1  PHYLUM Bryophyta% (mosses and liverworts)
       1  Anthocerotopsida
       2  Hepaticopsida
       3  Bryopsida
       4  {{Tracheophyta}}
           (= Pteridophyta + Spermatophyta)

_1_ PHYLUM Pteridophyta%
       1  Horneophytopsida
       2  Plesion Aglaophyton
       3  Rhyniopsida
       4  Lycopsida (club mosses)
       5  Trimerophytopsida
       6  Cladoxylopsida
       B  Sphenopsida (horsetails)
       C  Filicopsida (true ferns)
       7  Plesion Pertica
       8  Progymnospermopsida%
      _a_ {{Spermatophyta}}
            (= Pinophyta + Magnoliophyta)

NOTES:   Within the Bryophyta, it is still hotly debated whether Anthocerotopsida split off before Hepaticopsida or vice versa.  I could have continued including Horneophytopsida and Plesion Aglaophyton within Rhyniopsida, but this is one paraphyletic Class I am willing to let go for the sake of harmony (that should please the strict cladists).   And for those of you care, Pteridophyta clade 6 (Cladoxylopsida + Sphenopsida + Filicopsida) has been named Moniliformopses.  Why not just call it the "moniliformopsian clade" instead of formalizing it?  In any case, don't be surprised if Cladoxylopsida turns out to be paraphyletic (but I betcha it was a strict cladist who proposed it)!!
     ---- Ken Kinman

More information about the Taxacom mailing list