Monday, February 28, 2011

Lottery Odds























This is a female flower of a hazel Corylus avellana. In about six months time it will have developed into a cluster of hazel nuts but for now, at the base of those beautiful carmine red stigmas there are female egg cells, each waiting to be fertilised by a pollen grain that will land on one of those stigmas, germinate and produce a microscopic tube that will transport the male nuclei down to the site of fertilisation. First, though, the pollen has to reach the stigmas - and that is a very chancy business.


Tap a twig covered in dangling male catkins on a still day and they'll release a cloud of pollen grains that will hang in the air for a second then disperse. If there's any kind of wind (and there usually is in spring) they'll be whisked away immediately, diluted in a vast volume of air and fall to ground who knows where - or maybe be destroyed by rain. The chances of one actually landing on a receptive stigma is small. Very small. Which is why wind pollinated trees like hazel need to be so profligate when it comes to producing pollen.

For every female  egg cell, embedded deep within this bud, it has been calculated that the tree produces 2,549,000 pollen grains. So next time someone uses the phrase 'the economy of nature' and waffles about how living organisms are 'perfectly adapted' there can only be one response: nuts. Hazel nuts.

12 comments:

  1. Educational - and it brought a smile to my face!! Thank you Phil!

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  2. Well, that explains why my hazelnuts never got any nuts. I was so terribly hopeful last year when I found two of the shrubs just loaded with flowers. But, come fall, not a single nut graced their branches. Now I know why. Should've taken the initiative and pollinated them myself with a paint brush!

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  3. Cracking stuff Phil, i'll be out examining the Hazels tomorrow.

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  4. Fascinating. I always learn when I visited.

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  5. Brilliant......amusing and informative. Pity the odds couldn't be stacked that high for some people I know.

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  6. And some wonderful photos too. Thanks Phil.

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  7. Hi Ellen, Just to make pollination even more of a challenge, some hazel bushes produce their male catkins first while others produce the female flowers first, while some produce them both together. I've got ahazel in my garden that never produces nuts.

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  8. Hi John, If you get a really still day when the catkins are shedding pollen (rare, I know) and tap a branch you get an amazing cloud of pollen that vanishes in a second of two - a bit like a ghostly apparition!

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  9. Hi Adrian, there's another factor that stacks the odds against nut production too - around here the grey squirrels take them long before they ripen.

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  10. Hi Toffeeapple, I just love that shade of carmine red that the stigmas have...

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