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Author Topic: Why do autumn crocus flower when they do?  (Read 5762 times)

Anthony Darby

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Re: Why do autumn crocus flower when they do?
« Reply #15 on: October 24, 2008, 09:18:19 AM »
Yes, we know what bulbs are intended to achieve from the plants' point of view, but I think Ian is meaning that we should look beyond that to a reason for the underground ovary etc...... ::)

I would suggest it would be foolish to expose your bits to the sky until they are ready. Ovaries are a nutritious food source so there is no point in putting your eggs in an obvious and visible basket until it is time for dispersal?
Anthony Darby, Auckland, New Zealand.
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Gerry Webster

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Re: Why do autumn crocus flower when they do?
« Reply #16 on: October 24, 2008, 10:01:11 AM »
Yes, we know what bulbs are intended to achieve from the plants' point of view, but I think Ian is meaning that we should look beyond that to a reason for the underground ovary etc...... ::)
I would suggest it would be foolish to expose your bits to the sky until they are ready. Ovaries are a nutritious food source so there is no point in putting your eggs in an obvious and visible basket until it is time for dispersal?

Anthony - one of my Sternbergias currently has its bits exposed & I presume they are nutritious since they are being eaten by something.
Martin Rix has a not very illuminating discussion of the subterranean ovary in his book Growing Bulbs. He lists 22  genera which possess it & in which it probaby originated independently.
Gerry passed away  at home  on 25th February 2021 - his posts are  left  in the  forum in memory of him.
His was a long life - lived well.

Ian Y

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Re: Why do autumn crocus flower when they do?
« Reply #17 on: October 24, 2008, 11:56:42 AM »
Wonderful - now I have you all trying to solve my dilemma.

So often we are conditioned to think within certain parameters - but I always try and break the boundaries and look at all possibilities.

I have always assumed or been taught that autumn flowering bulbs are flowering 'out of season' unlike their spring relatives which are 'in season' but is this the case?

To broaden this discussion can anyone offer any reason why there are no autumn flowering fritillarias?

Ian Young, Aberdeen North East Scotland   - 
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Anthony Darby

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Re: Why do autumn crocus flower when they do?
« Reply #18 on: October 24, 2008, 12:37:48 PM »
Yes, we know what bulbs are intended to achieve from the plants' point of view, but I think Ian is meaning that we should look beyond that to a reason for the underground ovary etc...... ::)
I would suggest it would be foolish to expose your bits to the sky until they are ready. Ovaries are a nutritious food source so there is no point in putting your eggs in an obvious and visible basket until it is time for dispersal?

Anthony - one of my Sternbergias currently has its bits exposed & I presume they are nutritious since they are being eaten by something.
Martin Rix has a not very illuminating discussion of the subterranean ovary in his book Growing Bulbs. He lists 22  genera which possess it & in which it probaby originated independently.

By there very nature, sternbergias have their ovaries on a stem. Crocus flowers have their ovaries under ground. The stem only elongates when the seeds are ripe, which makes sense.
Anthony Darby, Auckland, New Zealand.
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http://www.dunblanecathedral.org.uk/Choir/The-Choir.html

Gerry Webster

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Re: Why do autumn crocus flower when they do?
« Reply #19 on: October 24, 2008, 02:34:37 PM »
Yes, we know what bulbs are intended to achieve from the plants' point of view, but I think Ian is meaning that we should look beyond that to a reason for the underground ovary etc...... ::)
I would suggest it would be foolish to expose your bits to the sky until they are ready. Ovaries are a nutritious food source so there is no point in putting your eggs in an obvious and visible basket until it is time for dispersal?
Anthony - one of my Sternbergias currently has its bits exposed & I presume they are nutritious since they are being eaten by something.
Martin Rix has a not very illuminating discussion of the subterranean ovary in his book Growing Bulbs. He lists 22  genera which possess it & in which it probaby originated independently.
By there very nature, sternbergias have their ovaries on a stem. Crocus flowers have their ovaries under ground. The stem only elongates when the seeds are ripe, which makes sense.
Anthony - sorry, I obviously  didn't make my point clearly enough. I was wondering why, if it was a so advantageous,  Sternbergias  did not also have subterranean ovaries - though I believe S. clusiana effectively does. With respect to crocus, I also wonder to what extent the supposed advantages of subterranean ovaries are offset by the enormous distance the pollen tube is required to grow - up to 10cm or so.   
Gerry passed away  at home  on 25th February 2021 - his posts are  left  in the  forum in memory of him.
His was a long life - lived well.

Oron Peri

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Re: Why do autumn crocus flower when they do?
« Reply #20 on: October 24, 2008, 02:52:30 PM »
I have always assumed or been taught that autumn flowering bulbs are flowering 'out of season' unlike their spring relatives which are 'in season' but is this the case?

To broaden this discussion can anyone offer any reason why there are no autumn flowering fritillarias?

Ian,

I do not believe that there is 'out of season' or 'in season', I think it all relates to the competition after pollinators, in spring there are much more flowers around which makes a lower Chance for a bee to find you.
While in Autumn there are much less flowers and so you have a better chance, I think evolution created this separation of plants that had better results in terms of continuity of the species by flowering in spring or autumn.

As for your Fritillarias question:

Frits. have a soft bulb meaning it doesn't have a sufficient protection against drought, not as in the case of Crocus and most other geophytes that have layers of tunic, and so the solution is to go deeper and deeper in the ground,
for example,in the case of F. arabica [persica f. arabica], in the desert we once degged for a bulb that was 60cm deep in the ground.
Now, if it had to flower in Autumn , it means it would have to grow a stalk of at least 1.2 meters high, through a soil that is hard and dry as a rock.
Having a relatively small sized bulb i assume it would be almost impossible without available water.

Urgineas for example have a Hugh bulb that can weight a few kg [full of water] heaving the neck on the surface or just below and so it can afford  blooming in Autumn.

My answers are only thoughts that I share and not scientifically proved...
« Last Edit: October 24, 2008, 03:49:41 PM by Oron Peri »
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Anthony Darby

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Re: Why do autumn crocus flower when they do?
« Reply #21 on: October 24, 2008, 03:59:01 PM »
Yes, we know what bulbs are intended to achieve from the plants' point of view, but I think Ian is meaning that we should look beyond that to a reason for the underground ovary etc...... ::)
I would suggest it would be foolish to expose your bits to the sky until they are ready. Ovaries are a nutritious food source so there is no point in putting your eggs in an obvious and visible basket until it is time for dispersal?
Anthony - one of my Sternbergias currently has its bits exposed & I presume they are nutritious since they are being eaten by something.
Martin Rix has a not very illuminating discussion of the subterranean ovary in his book Growing Bulbs. He lists 22  genera which possess it & in which it probaby originated independently.
By there very nature, sternbergias have their ovaries on a stem. Crocus flowers have their ovaries under ground. The stem only elongates when the seeds are ripe, which makes sense.
Anthony - sorry, I obviously  didn't make my point clearly enough. I was wondering why, if it was a so advantageous,  Sternbergias  did not also have subterranean ovaries - though I believe S. clusiana effectively does. With respect to crocus, I also wonder to what extent the supposed advantages of subterranean ovaries are offset by the enormous distance the pollen tube is required to grow - up to 10cm or so.   
The question is biologically irrelevant. You might as well say why don't Agapanthus have subterranean ovaries. If your ovaries start off underground, no point in exposing them too soon. That's the way these crocuses have evolved. There is not one solution fits all. Sternbergia flowers are on a stem clear and simple.
Anthony Darby, Auckland, New Zealand.
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http://www.dunblanecathedral.org.uk/Choir/The-Choir.html

Gerry Webster

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Re: Why do autumn crocus flower when they do?
« Reply #22 on: October 24, 2008, 04:48:04 PM »
The question is biologically irrelevant.

Well Anthony,  I think that is debatable, but the pages of the SRGC forum do not seem an appropriate place to debate issues in theoretical biology.
« Last Edit: October 24, 2008, 04:50:13 PM by Gerry Webster »
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Ian Y

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Re: Why do autumn crocus flower when they do?
« Reply #23 on: October 24, 2008, 07:49:29 PM »
Oron, thanks for your thoughts on my Fritillaria question they are good points and I will think about them - but it is a fact that some fritillarias share the same habitat as crocus both summer and spring flowering so there is no simple answer.
I agree with you that pollinators must play a very big part in the evolutionary development of these bulbs and when they flower they are possibly more influential than climate alone.
Ian Young, Aberdeen North East Scotland   - 
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