Date: Thu, 18 Jun 1998 17:45:00 From: SCHLAUER@chemie.uni-wuerzburg.de To: cp@opus.hpl.hp.com Message-Id: <aabcdefg2088$foo@default> Subject: Re: More on Nelson and Casper
Dear Loyd & al.,
>>However, a phototype is always a photograph of a
>>dried or preserved specimen, not of a living plant.
>
> Given the fragility of these things, I would have thought
> that good photographic records would hold some advantages
> over dried specimens.
You can certainly examine the ultrastructure or the chemical
compounds present in a photograph, but I predict the results to
differ significantly from those obtained with dried specimens.
> Are there major objections to photographic material which prevents
> changes to the extant rules?
See above.
> I can appreciate why Nelson did not want to remove one of these
> plants for this purpose and consider his approach more innovative
> than eccentric.
I would not recommend this kind of innovation for future taxonomic
work. It prevents the application of other innovative methods.
> Also Nelson states 'To designate the variant with a white
> corolla as a variety is extravagant' would you care to
> comment on this statement Jan?
This is a matter of opinion. The only rules for infraspecific taxa
are those of inclusivity:
A species may include several subspecies, varieties, and/or forms.
A subsp. may include several vars. and/or ff.
A var. may include several ff.
A f. cannot include several vars., subspp., or spp.
A var. cannot include several subspp. or spp.
A subsp. cannot include several spp.
What is a subsp., var. or f. is not defined anywhere in the ICBN
(OK, they are infraspecific ranks, but not even the meaning or
significance of this fact is explained to any sensible degree).
BTW: Yes, Michael, Stuessy writes a lot. But unfortunately (or
rather, fortunately?) Stuessy is not a collection of rules that
*must* be followed but only one of the numerous possible *opinions*.
Whether anthocyanin-negative (mostly double-negative, if the
plants are diploid) mutants should be considered taxa independent
from their positive relatives (and most probably also their positive
ancestors!) is rather disputable. I do not attach any significance in
terms of speciation to these occasionally occurring individuals/
populations. But it may be argued that perhaps some strange insect
prefers just the white flowers, so these plants are ad hoc sexually
separated from their ancestors.
If it could be demonstrated that such a reproductive mechanism in
fact leads to separation of taxa (i.e. if other, genetically
independent and distinct features are correlated with different
flower colour), I would tend to believe that it has some taxonomic
relevance.
RE: _P. hirtiflora f. pallida_
Juerg Steiger and I have been to what must be very close to the type
locality of this plant (Mt. Korax, Vardoussia, Greece) more than
hundred years after Heldreich. We did find plants of hirtiflora (more
recently classified as a subspecies of _P. crystallina_ by Strid)
but there was not an appreciable difference - except the usual
variability - in the flower colour. Even if purely white flowered
specimens did exist on the Korax, this population was just too close
to normal plants to show any taxonomic independence. The form is duly
reduced to synonymy with _P. crystallina subsp. hirtiflora_ in the
cp database.
RE: f. chionopetra and conservation
My personal impression is that anthocyanin-negative mutants are far
more likely to be pollinated, propagated, and preserved by some weird
humans commonly called cp growers than by an (at the moment purely
hypothetical) insect exclusively visiting white flowers. Therefore,
the best measure to protect the mutant would have been to establish
it in cultivation and to select the plant as a cultivar.
If the Burren is threatened (is it?) in its being a _P. grandiflora_
biotope, naming a mutant as a taxon of disputable value will not help
much.
Kind regards
Jan
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