Has the Recent Evolution of Stemless Dandelions Been Discussed in

Discussion in 'Health and medical' started by Jeffrey Turner, Feb 13, 2004.

  1. I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    biologist and am curious about this, can anyone give me some information? Thanks.

    --Jeff

    --
    Ho, ho, ho, hee, hee, hee and a couple of ha, ha, has; That's how we pass the day away, in the merry
    old land of Oz.
     
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  2. John Wilkins

    John Wilkins Guest

    In article <[email protected]>,
    Jeffrey Turner <[email protected]> wrote:

    > I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    > lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    > biologist and am curious about this, can anyone give me some information? Thanks.
    >
    > --Jeff

    Possibly individual adaptation - longer grass means it has to grow further to release its seeds, but
    in trimmed lawns it doesn't need to. Basically, when it hits the full sun, it will seed:

    http://www.geocities.com/naturenotes/dandy.htm

    --
    John Wilkins [email protected] www.wilkins.id.au It is not enough to succeed. Friends must be
    seen to have failed. Truman Capote
     
  3. Tim Tyler

    Tim Tyler Guest

    Jeffrey Turner <[email protected]> wrote or quoted:

    > I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    > lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    > biologist and am curious about this, can anyone give me some information? Thanks.

    Not just immature ones? I think they've always started flowering low:

    ``After blossoming, the inner involucre closes, the slender beak elongates and raises up the pappus
    while the fruit is forming, the whole involucre is then reflexed, exposing to the wind the naked
    fruit, with the pappus displayed in an open globular head."''

    - http://www.ibiblio.org/herbmed/eclectic/cook/TARAXACUM_DENS-LEONIS.htm
    --
    __________
    |im |yler http://timtyler.org/ [email protected] Remove lock to reply.
     
  4. Tim Tyler wrote:
    > Jeffrey Turner <[email protected]> wrote or quoted:
    >
    >
    >>I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    >>lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    >>biologist and am curious about this, can anyone give me some information? Thanks.
    >
    > Not just immature ones? I think they've always started flowering low:
    >
    > ``After blossoming, the inner involucre closes, the slender beak elongates and raises up the
    > pappus while the fruit is forming, the whole involucre is then reflexed, exposing to the wind the
    > naked fruit, with the pappus displayed in an open globular head."''
    >
    > - http://www.ibiblio.org/herbmed/eclectic/cook/TARAXACUM_DENS-LEONIS.htm

    No, these dandelions have no scape. The flower grows directly at the point where the leaves meet. It
    seems like true genetic evolution not Lamarckian adaptation. Any idea how I'd go about publishing
    this? Thanks again.

    --Jeff

    --
    Ho, ho, ho, hee, hee, hee and a couple of ha, ha, has; That's how we pass the day away, in the merry
    old land of Oz.
     
  5. SeeBelow

    SeeBelow Guest

    Jeffrey Turner wrote:
    >
    > I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    > lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    > biologist and am curious about this, can anyone give me some information? Thanks.

    I agree with your hypothesis. I would be surprised if no one has researched this before, but perhaps
    no academic type has paid attention to his lawn.

    Have you done a citeseer search on dandelion evolution?

    m

    --
    "Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal." -
    Friedrich Nietzsche

    http://annevolve.sourceforge.net is what I'm into nowadays. Humans may write to me at this address:
    zenguy at shaw dot ca
     
  6. Malcolm

    Malcolm Guest

    "Jeffrey Turner" <[email protected]> wrote in message
    >
    > No, these dandelions have no scape. The flower grows directly at the point where the leaves meet.
    > It seems like true genetic evolution not Lamarckian adaptation. Any idea how I'd go about
    > publishing this?
    >
    You need to do a literature search to make sure that no-one else has spotted the same thing. You
    will also certainly find out things of relevance, which you can cite. It helps if you have access to
    a university library and a search engine called "Web of Science" which indexes recent papers by
    subject and by citation. Then you've got to make sure that you are genuinely observing a genetic
    difference. You could try growing some new and old dandelions under identical conditions. If the
    difference isn't totally clear-cut you then do statistical analysis of the populations. A research
    journal would love to know the gene involved, or the proximate mechanism. This is probably beyond
    your resources, and since dandelions are

    to get some botanist with access to a modern lab involved. Choose a journal that accepts short
    articles, and submit it. Since you are not an academic they will probably referee it more thoroughly
    than usual, but if there is a genuine discovery here then the referees will want to help you get it
    published, so they will suggest improvements. Don't throw away your experimental materials in case
    someone wants to inspect them. Good luck.
     
  7. Wirt Atmar

    Wirt Atmar Guest

    SeeBelow Nut writes:

    >Jeffrey Turner wrote:
    >>
    >> I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    >> lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    >> biologist and am curious about this, can anyone give me some information? Thanks.
    >
    >I agree with your hypothesis. I would be surprised if no one has researched this before, but
    >perhaps no academic type has paid attention to his lawn.

    The effect is well known and has been noted for at least two hundred years. While your observations
    are to be commended -- and there is undoubtedly a form of selection going on -- the effect is almost
    certainly wholly epigenetic. It is not likely to be the result of the mower's direct selection for
    that certain percentage of the dandelion population that flowers lower to the ground and is thus not
    heritable variation.

    When plants are stressed, they switch from vegetative to reproductive (flowering) growth patterns.
    While this stress is most normally induced by drought, any form of stress: mechanical mowing,
    herbivory, disease, etc. may be sufficient to switch the plant into a "desperation" strategy of
    attempting to

    expires.

    Horticulturalists have long used this effect to time fruit set in their crops. Although the short
    note below contains a number of misspelled words, the author very clearly conveys the commonality of
    the knowledge:

    http://plant-tc.coafes.umn.edu/listserv/2003/log0308/msg00113.html

    If you go to Google and type in the phrase:

    stress plant switch vegetative reproductive

    you'll find hundreds of pages explaining the phenomenon. Perhaps more importantly, there have been
    tens of thousands of papers published on the subject, particularly in agronomy and horticulture.

    Wirt Atmar
     
  8. Malcolm wrote:
    > "Jeffrey Turner" <[email protected]> wrote:
    >
    >>No, these dandelions have no scape. The flower grows directly at the point where the leaves meet.
    >>It seems like true genetic evolution not Lamarckian adaptation. Any idea how I'd go about
    >>publishing this?
    >
    > You need to do a literature search to make sure that no-one else has spotted the same thing. You
    > will also certainly find out things of relevance, which you can cite. It helps if you have access
    > to a university library and a search engine called "Web of Science" which indexes recent papers by
    > subject and by citation. Then you've got to make sure that you are genuinely observing a genetic
    > difference. You could try growing some new and old dandelions under identical conditions. If the
    > difference isn't totally clear-cut you then do statistical analysis of the populations. A research
    > journal would love to know the gene involved, or the proximate mechanism. This is probably beyond
    > your resources, and since dandelions are

    > to get some botanist with access to a modern lab involved. Choose a journal that accepts short
    > articles, and submit it. Since you are not an academic they will probably referee it more
    > thoroughly than usual, but if there is a genuine discovery here then the referees will want to
    > help you get it published, so they will suggest improvements. Don't throw away your experimental
    > materials in case someone wants to inspect them. Good luck.

    Thanks, I'll look into it. I never thought I'd grow dandelions on purpose. :)

    --Jeff

    --
    Ho, ho, ho, hee, hee, hee and a couple of ha, ha, has; That's how we pass the day away, in the merry
    old land of Oz.
     
  9. Anon.

    Anon. Guest

    [email protected] wrote:
    > Jeffrey Turner wrote:
    >
    >>I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    >>lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    >>biologist and am curious about this, can anyone give me some information? Thanks.
    >
    >
    > I agree with your hypothesis. I would be surprised if no one has researched this before, but
    > perhaps no academic type has paid attention to his lawn.
    >
    > Have you done a citeseer search on dandelion evolution?
    >
    For what it's worth, I've tried a few searches in Web of Science, and found nothing.

    I can only assume that any academic botanist rich enough to own a lawn is either out of active
    research, or so rich that they can employ their own gardener.

    Bob

    --
    Bob O'Hara

    Dept. of Mathematics and Statistics
    P.O. Box 4 (Yliopistonkatu 5) FIN-00014 University of Helsinki Finland Telephone: +358-9-191 23743
    Mobile: +358 50 599 0540 Fax: +358-9-191 22 779 WWW: http://www.RNI.Helsinki.FI/~boh/ Journal
    of Negative Results - EEB: http://www.jnr-eeb.org
     
  10. Anon.

    Anon. Guest

    Wirt Atmar wrote:
    > SeeBelow Nut writes:
    >
    >
    >>Jeffrey Turner wrote:
    >>
    >>>I have noticed the existence of stemless dandelions, ostensibly driven by the advantage of being
    >>>lower than lawn mower blades. Has this phenomena been published? I'm neither a botanist nor
    >>>biologist and am curious about this, can anyone give me some information? Thanks.
    >>
    >>I agree with your hypothesis. I would be surprised if no one has researched this before, but
    >>perhaps no academic type has paid attention to his lawn.
    >
    >
    > The effect is well known and has been noted for at least two hundred years. While your
    > observations are to be commended -- and there is undoubtedly a form of selection going on -- the
    > effect is almost certainly wholly epigenetic. It is not likely to be the result of the mower's
    > direct selection for that certain percentage of the dandelion population that flowers lower to the
    > ground and is thus not heritable variation.
    >
    Whilst I agree with Wirt, I would also like to point out that dwarfing genes are well onown in
    plants - there are wheat varieties that flower when they're only a few centimetres high.

    Of course, someone could actually do an experiment to compare these two hypotheses. All it would
    need would be seed from several dandelions, and a reasonably well stocked glasshouse (alas I have
    neither). Or is the suggestion of doing real science a faux pas here?

    Bob

    --
    Bob O'Hara

    Dept. of Mathematics and Statistics
    P.O. Box 4 (Yliopistonkatu 5) FIN-00014 University of Helsinki Finland Telephone: +358-9-191 23743
    Mobile: +358 50 599 0540 Fax: +358-9-191 22 779 WWW: http://www.RNI.Helsinki.FI/~boh/ Journal
    of Negative Results - EEB: http://www.jnr-eeb.org
     
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