[Taxacom] PhyloCode & ICZN to "duke it out"?

Paul van Rijckevorsel dipteryx at freeler.nl
Thu Oct 4 02:28:43 CDT 2007

I would like to repeat the point that a Code of nomenclature is just that.
It is not bound up with a taxonomy, or with any particular taxonomic
viewpoint. Any Code is a set of rules that allows a taxonomic viewpoint to
be expressed.

At some point I asked Kevin de Queiroz about ranks, and he said (IIRC) that
the PhyloCode does not prohibit ranks: it is just silent on the topic.
Followers of the PhyloCode may use ranks, if it makes them happy.

Basically any taxonomic viewpoint on plants can be expressed using the ICBN.
There is a practical limit on the number of ranks that can be used, but not
a formal one (Art 4.3).

For all practical purposes, the ICBN has always known and accepted rankless
names, such as Chlorophyta, Angiospermae, Coniferae, etc. Formally speaking
these names are not rankless (in a given book, if sufficiently detailed,
they will have a rank), but they are not bound to a particular fixed rank:
they "may be used unchanged at different ranks." (Art 16.1(b)).

It is true that under the ICBN, a family cannot be contained in another
family (and a genus not in another genus), but there are no requirements on
what constitutes a family. There is even no requirement that a taxonomist
assigning ranks should adopt a fixed set of criteria on family delimitation:
he is at liberty to elevate taxa with minor differences to the rank of
family in one order, while in a different order (in the same publication) he
lumps taxa with major differences into one family.

Finally the point that although there is now a whole crop of new names in
use for plant groups (asterids, lamiids, malvatheca), this does not
necessarily mean that these new names MUST be regulated by a Code. In both
plant and animal nomenclature there was something like a century of usage
before efforts to codify started. And then something like half a century, or
more, before the Codes reached a form which we now recognise.
There is no rush.


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