Date: Sun, 14 Jun 1998 19:20:20 +0200 From: juerg.steiger@iae.unibe.ch (Juerg Steiger) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg2025$foo@default> Subject: Re: Albino or 'Forma'?
After some days of absence I see different contributions concerning P.
grandiflora f. chionopetra from Ireland. May be the Bonn conference was
the trigger, and for the non-participants I quote here what I wrote in my
Bonn paper:
"A pure white form of P. grandiflora was found in the Burren Mountains
south of the Galway Bay (Co. Clare) in Ireland by Webb in 1956 and later by
Nelson in 1991, who described it as P. grandiflora f. chionopetra (Nelson
1993). I have seen one fresh specimen from there which was not pale blue as
the f. pallida but really white. Whitish or pale blue P. grandiflora were
also found by other authors in Co. Kerry, but the pure white forms seem to
be really rare. If these are to be considered as occasional albinos as they
occur in many violet plant species or if they should be ranked as a forma
is subject of individual viewpoints."
I showed a color slide of a pure white P. grandiflora (from the Irish
Galway Bay) and added my personal opinion that - in contrast to the f.
pallida - I consider the pure white form to be an albino mutation and no
'forma'. Albinos disappear usually after the individuals death as they are
mostly rare (no numerical opportunity for albino-albino
heteropollinations), they may be inattractive for pollinators and their
heredity is recessive.
I totally agree with Paul Temple that it is nonsense to give occasional
albinos the rank of a 'forma'.
The P. grandiflora f. pallida presents a different pattern. At some places
in the Jura Mountains it amounts to 20% of all specimens and I even know a
site in France where only the f. pallida occurs (hundreds of specimens). In
this case the pale coloured mutation - if it occurs - has obviously some
positive selection characteristics (e.g. specific pollinators which prefer
pale colours etc.) which enable it to compete successfully with the dark
violet specimens. If the colour deviation is combined e.g. with a mutation
of a slightly different ecological preference which is coincident with the
habitat of an inclined pollinator, this may be the beginning of the
evolution of - after 500'000 years or so - a new variety or subspecies or
even species.
Juerg
Juerg Steiger M.D., Institute for Medical Education IAWF,
University of Bern, Faculty od Medicine, Inselspital 37a, CH-3010 Bern,
Switzerland. Phone: +41 (0)31 632 9887, Fax: +41 (0)31 632 9871
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