[HN Gopher] New sunflower family tree reveals multiple origins o...
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       New sunflower family tree reveals multiple origins of flower
       symmetry
        
       Author : pseudolus
       Score  : 28 points
       Date   : 2024-04-04 11:17 UTC (2 days ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | iefbr14 wrote:
       | > The sunflower head, for example, is actually a composite
       | composed of multiple much smaller flowers. While the head is
       | generally radially symmetric--it can be divided into two equal
       | halves in multiple directions..
       | 
       | When you look at the seeds in the head you will noticed that they
       | form a spiral. A spiral doesn't have a radial symmetry afaik.
        
         | mathgradthrow wrote:
         | _one_ spiral does not have radial symmetry. If i take the union
         | of that spiral and that spiral rotated by 2pi*k /n rotation for
         | each k, I get n-fold symmetry.
        
       | pvaldes wrote:
       | Asteraceae is a spectacularly successful and very complicate
       | family to classify the same time. Very easy to spot at family
       | level, but a lot of tribes and a nightmare of details at species
       | level
       | 
       | The (real) flowers are "trumpet" like, thin and long ended in a
       | small star, but the extreme of this trumpet can be arranged in
       | several ways, as the article explains. It seems that this shape
       | evolved several times in the (28000 yet?) species known. The
       | success of is family as plants can be compared with 'beetle'
       | level of success on animals.
        
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       (page generated 2024-04-06 23:01 UTC)