Re: Hybrids & variety confusion

From: Peter Cole (carnivor@flytrap.demon.co.uk)
Date: Thu Feb 18 1999 - 01:45:33 PST


Date: Thu, 18 Feb 1999 17:45:33 +0800
From: Peter Cole <carnivor@flytrap.demon.co.uk>
To: cp@opus.hpl.hp.com
Message-Id: <aabcdefg493$foo@default>
Subject: Re: Hybrids & variety confusion

on Sat, 13 Feb 1999 15:23:43 -0000
"NEIL ARMSTRONG" <n.armstrong@virgin.net> wrote:

> Dear William & List,
> I thought I would give my two penny's worth on this subject.
> I only discovered recently that most non CP hybrids are sterile, (I grow
> CP's, but I'm no gardener). I suppose that we take for granted that "our"
> plants can be crossed every which way, but it has led to huge confusion,

        True with many (most perhaps), but don't forget that almost all
        interspecific Drosera hybrids are sterile (in itself perhaps a good
        reason to regard D.burmanii + sessilifolia as synonymous or at least
        subspecies), and that we know almost nothing about Utricularia
        hybrids - the genus that accounts for ~1/3 of all carnivorous species.
        Out of the ~14 genera of carnivorous plants, I'm only aware of 3 or 4
        that produce fertile interspecific hybrids routinely(-ish) - Sarracenia,
        Heliamphora, Nepenthes and Pinguicula(?), and none that will hybridise
        intergenerically. If you want to see total hybrid chaos, find a book
        on orchids and have a look at some of the hybrid parentages!

> especially with Sarracenia hybrids which now seems to be completely out of
> control. Know one seems to know anymore if a plant is genuine or miss-
> labled. Another problem we seem to have at the moment is the question over
> wether long standing variety's are what we thought they were, for example,
> is S. Maxima a seperate variety, or just a large form of S. Flava, common

        It is a distinct form (I'm not sure if it has been properly described
        as a cultivar - I'm sure Jan will let us know! :) but is no larger
        than many (most?) other flava forms - it is identifiable by the almost
        complete lack of red veining, and the very distinctive roundish,
        incurved lid. I find it consistently shorter than many S.flava, most
        S.alata and the very nice Marstons' S.alata*flava'maxima' which is
        probably my favourite Sarracenia.

> in the wild? This leads to huge problems for the average grower, especially
> if they breed and sell to an unsuspecting person, labelling becomes
> meaningless.

        All too often true I'm afraid. This is a nightmare genus for taxonomists,
        as it has been bred and hybridised for well over a century in cultivation
        often by growers with little or no understanding of taxonomy.

> I read with interest Peter D'Amato's new book (Very good by the way) about
> the variety of new VFT's that are springing up are Tissue Culture mutants,
> is this a worrying trend?

        It depends - if I ever meet a 9-foot sentient D.muscipula var.triffidus,
        I'll let you know :)

> Could this happen to more species?

        It can happen to any species in vitro - genetic mutation is quite common
        in tissue that is multiplied by tissue culture, especially when cell-lines
        are recultured over many generations. Mutation is the primary means by
        which new species are naturally created, but in controlled conditions,
        unfavourable mutations can survive where they would not have in the wild,
        not least because they may be specifically selected by growers for their
        unusual colour or shape. Take the 'cup-tooth' VFT for example - it is
        at a tremendous disadvantage over a 'regular' plant, being unable to
        catch insects. If it arose in nature, it would most likely die out before
        reproducing, but it is kept alive by growers who want something unusual
        in their collection. I suppose it might be considered worrying if there
        was any danger of vigorous mutants getting into the wild gene-pool, but I
        have yet to see any Dionaea mutants (the main genus that seems to be
        currently affected,) that in any way out-perform the 'regular' wild plants.
        This may explain the lack of a wide variety of naturally occurring forms
        (compared to, say, N.alata.)
        
        I'd worry a lot more about economically important crop-species that could
        be damaged than about CPs, which in the grand scheme of things are
        relatively insignificant ornamentals.
        That's not to say they're less important than other species, but the risk
        is so much smaller by virtue of the fact that only a few thousand people
        worldwide have modest personal collections (often thousands of miles away
        from the wild habitat,) compared to the trillions of wheat and rice plants
        (for example) that are grown each year. And even with such species, viruses,
        pests and diseases are far more of a risk than incidental mutation (which
        occurs naturally anyway.)
        It goes without saying, of course, that such specimens should never be
        deliberately introduced into the wild (I said "very little", not "no"
        danger.)

                Happy growing,

                                Peter

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