Date: Mon, 12 Jan 1998 14:00:04 From: SCHLAUER@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg145$foo@default> Subject: Re: Anthocyanin free Darlingtonia - nomenclature
Dear Wim,
Barry has had some email problems recently, but possibly I can
comment on some of your questions:
> You write that you "do not want to see that invalid name [Darlingtonia
> californica F. heterophylla] thrown around by growers!". Can you tell me
> why this would be invalid and when one can speak (nomenclatury correct)
> of a subspecie, form, ...
As you will probably know (but perhaps there are some listeners who
would like to read this as well), there are principally two different
aspects in a scientific plant name: taxonomy and nomenclature.
Taxonomy is the process of grouping organisms into mutually exclusive
entities (taxa).
Nomenclature is the process of naming these entities correctly.
The rules (International Code of Botanical Nomenclature) apply only
to the latter process. Any name published according to these
formal rules is *valid* (or "nomenclaturally correct"). This does
*NOT* mean that this name has to be *accepted* (or "taxonomically
correct") by all authors. There are in fact a lot of valid names that
are nevertheless considered (taxonomic) synonyms of other names by at
least some authors.
The problem with the white _Darlingtonia_ is its not yet established
taxonomic status. Perhaps some people think it should be segregated
from the normal (anthocyanin-containing) plants, and others do not.
If it is to be segregated, the rank (form, variety, subspecies) has
to be determined at which it should be separated. While the rank may
not matter much in taxonomy (as long as the relative limits of the
groups are clear; in our case _D. californica_ as a species would
clearly include the white plants at some rank below species), it is
quite essential for nomenclature (any newly described taxon must have
a clearly stated rank).
There are some people (incl. myself) who think that a taxon at
whatever rank must have some evolutionary meaning (i.e. represent an
adaptation to environmental factors). In a complicated biosynthesis
like for anthocyanins, there are plenty of possibilities for mutations
to preclude formation of the final metabolite. Still, an anthocyanin-
free plant does survive because its primary metabolism is not or only
marginally affected by the defect. Only after generations (if at
all), the different colouration of the flowers will lead to decreased
cross-fertilization, i.e. to genetical drift, i.e. potentially to the
elimination of such mutants from a population. In the meanwhile other
mutants may appear that have the same phenotype (even if the mutation
occurred in another gene of the same pathway). This may even lead to
a +/- constant percentage of white plants within normal populations.
I therefore maintain that anthocyanin albinos (which are known in
almost any anthocyanin-containing species) do *not* have any
taxonomic relevance, as long as they do not constitute separated
populations that behave ecologically and chorologically independently
from their ancestral taxon. They can be of horticultural value, but
this is no taxonomic issue.
Kind regards
Jan
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