A feature of flowers of the compositae (Daisies, Dandelions etc) is the way that flowers structure themselves to fit Fibonacci numbers. (The Fibonacci series is 0,1,1,2,3,5,8,13,21,34,55 etc., where each succeeding number is the sum of the previous pair.) In this instance the anticlockwise and clockwise spirals in the yellow centre always appear as an adjacent pair from the series, in this case 21 and 34. (Not all individual flowers show quite as regular a pattern as this one.) Compare with
Link. There are also 21 of the white ray florets.
One of a series of pictures depicting wild flowers in Carlton Cemetery. The management of the as yet undeveloped section of the cemetery allows a number of traditional meadow flowers to flourish.
A slideshow of these flowers can be seen here
Link