The Dahlia Garden at the Conservatory of Flowers in Golden Gate Park. Photographed on the day of the Burn, September 2nd 2006.

Dahlias are octoploids (they have eight sets of homologous chromosomes, whereas most plants have two), so they can be bred to exhibit an incredible range of traits. There are over 35,000 officially registered varieties that all can be traced back to three simple original varieties from Mexico which had only eight petals around.

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