Saturday, April 2, 2011

A Dandelion with a Difference

I found this strange-looking dandelion in Newcastle this afternoon, growing beside a footpath in the city. Unlike typical dandelions (see picture below) which have a spiral whorl of florets each with as single long petal with a toothed tip, with very long petals around the margin of the flower head, this one had very short spoon-shaped petals throughout, so the flower resembled a pom-pom with numerous long styles, each tipped with a bifid stigma, sticking out of it. Quite decorative for a dandelion. There are mutant varieties of chrysanthemum sold commercially that are very similar in form - but a lot larger.



















This (above) is a typical dandelion inflorescence. Normally each individual dandelion floret is quite a complicated affair (see here for details) with the long style elongating through a tube of pollen-laden stamens, followed by the splitting of the stigma tip to reveal its receptive surface - a complex arrangement that is totally redundant because dandelions set seed without the need for any fertilisation by pollen, by a process called apomixis. The seeds that are produced are all clones of the parent - so in a week or two, when the flowers have run to seed, I'll go back to this abnormal plant and collect some - they should breed true and produce exact copies if this is a genetic mutant.
 
The other curious aspect of this mutant, seen here from above, is that all the florets are female - there is no trace of stamens or pollen. It seems the mutation that truncates the petals also inhibits the development of the stamens.

There's more on dandelions here.

10 comments:

  1. Amazing stuff Phil. Reading that blog entry took me longer than usual as I ended up following and exploring all the links to your earlier blogs on the subject. One of the great things about your blog is the seasonality and the knowledege that it's all happening out there, right now!

    I wonder if that means that Dandelions could be more prone to disease if they are genetically identical and have not reproduced sexually. I've read somewhere that this is a theory put forward for the wipe-out of English Elm due to Dutch-elm disease; i.e. it lacked genetic diversity.

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  2. Very interesting; it's a pretty looking thing isn't it?

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  3. Very interesting, how did you spot it? you've certainly got a keen eye.

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  4. the result of herbicides? Very attractive mutant though. Reminded me immediately of a chrysanth.

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  5. Funny you should mention that, QDanT, pollen sterility and apomixis of the kind that's present in these dandelions,could be bred into crop plants, so removing one of the objections to these crops - such plants would set seed but would not be able to transfer their genes to other plants.

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  6. That's an interesting point Dougie - being so genetically uniform, you'd expect them to suffer from disease epidemics but they show no sign of it - they're fantastically abundant at this time of year!

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  7. Hi Toffeeapple, I suspect that if dandelions weren't so invasive we'd probably want to cultivate them..

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  8. Hi David, I've always been interested in unusual varieties of wild flowers - I found a double-flowered lady's smock plant a while ago....

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  9. You could be right Pauline, but the plant looked healthy enough and so did the others around it ..... it'll be interested to see if the seedlings are the same.

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