Date: Mon, 08 Jun 1998 11:46:59 -0400 From: Michael <chambe58@pilot.msu.edu> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1952$foo@default> Subject: White-flowered forms
At 11:56 AM 6/5/98 -0700, you wrote:
>Not having read this paper, I will step well out of line and state -
>
>Oh no, not another named form based on flower colour.
Paul, I wholeheartedly agree with you about this.
White-flowered forms (also spineless forms, hairless forms, etc.) occur as
rare mutants in species throughout the plant kingdom. Individual mutants
may be rare, but the phenomenon is common. If we sought to name every odd
character state as a new form, it would turn simple regional floras into
encyclopedias of superfluous names. The botanical nomenclature system is
intended to name taxa, not this kind of variation.
Color forms usually occur sporadically in plant populations. In most cases
there is no evidence these color forms are breeding with their fellow
mutants. They are produced from phenotypically normal parents. If there's
evidence the color form is fertile and reproducing with its kind
(especially if it does not cross with normal plants) then there may well be
biological significance to the phenomenon. Rarely are such studies done
prior to naming of color forms.
White-flowered Sarracenia are believed to result from lack of anthocyanin
pigmentation. A mutation has disrupted the chemical pathway for
anthocyanin production. But which step in the pathway has been blocked?
The pathway could be blocked at any number of steps, resulting in the same
phenotype--an anthocyanin-lacking plant. But if you find
anthocyanin-lacking plants in two separate populations, do they share the
same mutation blocking the anthocyanin pathway? Or are they different
mutants, independently derived, sharing the same phenotype? It may seem
like a trivial point, but the two plants could be genetically different for
exactly the one character being used to designate the form. This is an
underlying problem with taxa defined by a single characteristic.
I'd like to encourage enthusiasts of odd forms to refer to these plants in
the common vernacular, as "white-flowered form, spineless form, hairless form"
rather than seeking to describe each with Latinized forma names (f. alba R.
Nixon, f. inermis Shmidlap, f. glabrata J.Doe). A simple description is
much clearer.
If the plant is of interest to horticulture, a lineage selected from wild
origin may be named as a cultivar. I am pleased to see in the updated FAQ
that Barry Meyers-Rice has chosen to name his anthocyanin-lacking
Darlingtonia discovery as a cultivar; Darlingtonia 'Othello' (though I am
perplexed by the choice of name, since Othello was not white :-)
A guide to naming cultivars can be found in the most recent issue of the
Carnivorous Plant Newsletter (March 1998, vol 27:1). Also in this issue is
a formal description of a yellow-flowered form, Sarracenia purpurea subs.
vernosa var. burkii f. luteola. As I understand it this yellow-flowered
plant is a textbook case of one fitting naming as a cultivar. Why it was
given a Latin forma name, in this issue no less, has me confused.
Michael
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