golden spiralling - but not out of control

Before the picture of the sunflower scrolls out of the main pages on the blog, I thought I'd mention that it's a 34.

I don't do it with most plants, but sunflowers require that special extra moment to (a) estimate and sometimes (b) count the number of petals. Not if they are a complete field full of flowers, you understand, but if they are singular.

Some people are surprised that flowers have set numbers of petals when they grow, but I think I'm 'amazed'. I know it is all about Fibonacci series and phi and golden means, but for some reason the sunflower is the perfect type of flower to check that nature is still working properly.

The right number of petals for flowers are (1), 2, 3, 5, 8, 13, 21, 34, 55, 89 and not really any other numbers (I know there's a few mutations, and so-called 'doubles' like on lilies, but let's stick with the main ones). The arithmetic is simply that the two previous numbers add up to the next available combination.

So my sunflower planted by the birds is a 34, and Pat's Michaelmas daisies are also 34s.

My picture of the complicated rose above is probably an 89, but it is a bit difficult to count the petals. I suppose that's the attraction of sunflowers for the purpose. They are easy to count.

The same thing happens with the spirally bit in the middle of a sunflower. The clockwise and the anticlockwise number of spirals are also in a similar ratio. It'll be something like 34 one way and 55 the other way.

Even pineapple bumps do it. Count the clockwise spirals and then the anti-clockwise ones. It'll be something like 13 one way and 21 the other.

There. I've managed to rationalise my flower petal counting. Now, back to the spreadsheets.