News from IAB

The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Friday, November 14, 2008

Classification discussion - two systems

Subject: RE: BRYONET: Classification discussion
Date: Fri, 14 Nov 2008 12:04:29 -0600
From: Richard Zander <>


Ken Kellman plunks for two separate systems, one focusing on clades, the
other allowing paraphyly. Sounds good, but remember that at least in my
opinion, clades do not reflect evolution, only genetic continuity and
isolation events. The Phylocode would be limited to classifications
based only on patterns of clades, which is good for some kinds of
research but not for others. In my opinion, the same evolutionary taxon
can appear in two different clades, as witness the overwhelming evidence
from "massive homoplasy" and fully cryptic species.

Ken hits the nail on the head, though, as he says:
"Perhaps the real problem comes when we try to blend the two systems as
in the Goffinet et al work that generated this whole discussion. This is
a hierarchical system that enforces strict monophyly."

The Goffinet et al. work (which might be called Moss Phylogeny Group
III) is a mighty contribution as a summary of recent study, don't get me
wrong. We are better for it. I am complaining only about the
disappearance of certain evolutionarily important taxa (Ephemeraceae,
Splachnobryaceae, Cinclidotaceae) by submerging them (at least in
Pottiaceae) without discussion, administratively, by invoking the
classification system called monophyly. I feel monophyly misrepresents
evolution in not recognizing strong and unique but nonmonophyletic
directions of evolution.

Does anyone have complaints about similar examples? Are there other
taxonomists who can't find their taxa?

Richard H. Zander
Voice: 314-577-0276
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166-0299 USA
Web sites:

No comments:

Post a Comment