Golden angle. Artwork showing the angle between repeating spirals in a floral pattern (yellow and white spheres). Each repeating spiral is 137.5 degrees apart. This angle is known as the 'golden angle' and is commonly found in plants, such as the angle separating florets on a sunflower head. The golden angle is mathematically related to the number Phi (1.618). It can be derived from the formula: 360 multiplied by 1 minus the reciprocal of Phi. Phi itself can be calculated from the Fibonaci series of numbers (1,2,3,5,8,13,21 etc) by dividing one Fibonacci number by the preceeding number in the sequence.