Robert Kuhn rkuhn at biology.UCSC.EDU
Thu Sep 1 12:07:06 EST 1994

I don't know the SciAm article you refer to, but it has always fascinated
me that not only sunflowers, but virtaully =all= plants use the spirals.
If you look at the spiral of the pine cone or the branches on a plant, you
will note that from one point, drawing a line up (or out) to the next branch
(or bract or seed) directly above it, the number of spirals in the right
and left direction required to get to that next spot will not be the same.
In fact the two numbers will be Fibonacci (sp??) numbers, from the Fib...
Series:  1,1,2,3,5,8,13,21,34,55,89,144, ....  I believe the sunflower
uses the last two.
	Best wishes,
			--b0b kuhn

Robert Kuhn, PhD              
Sinsheimer Laboratories       Shake and shake the ketchup bottle 
University of California      
Santa Cruz, CA 95064  USA     None will come.  And then a lot'll 
email: rkuhn at                    --Richard Armour

> From BIOSCI-REQUEST at Thu Sep  1 08:54:52 1994
> To: plant-biology at
> Subject: Sunflower seeds
> Nntp-Posting-Host:
> I believe that I have read an article in Scientific American about sunflowers
> (or at least sunflowers were mentioned in that article). The thing that 
> impressed me was, that the number of seeds in one blossom should be independent
> of the size of the blossom. Also the the placement of the seeds could be described
> by left- and right-winding logarithmic spirals.
> Unfortunately I can't find that article!
> Can anybody help me and provide the information either directly or by reference
> to the said article?
> Please answer by Email to
>      kapp at
> since I do not use news regularly.
> Thanks so long ...

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