Phyllotaxis, or how plants do maths when they grow

Abstract

Have you ever looked at a fir cone? Or a sunflower, or a pineapple? Almost certainly But have you noticed the regular spirals that cover them? Or counted those spirals? Probably not! We all think we know the things around us [1, 5]. But they can still hold surprises in store for us. In each of the above cases, if you count the number of clockwise and counter-clockwise spirals that cover the whole thing, you get two consecutive numbers in the Fibonacci sequence. This sequence, named after the thirteenth-century monk-mathematician who used it to describe the growth of a hypothetical population of rabbits, is formed by starting with 0 and 1 and defining the next number as the sum of the two preceding numbers. Thus: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, and so on. © 2011 Springer-Verlag Berlin Heidelberg.