1,1,2,3,5,8,13,21,34....... This series of numbers is known as the Fibonacci sequence. Here, the next number is obtained by adding the previous two numbers. Like, 1+1=2, 2+1=3, 3+2=5,..8+13=21, 13+21=34 and so on . Fibonacci found that this mathematical series is followed extensively in nature.These are some of the Fibonacci flowers. Above is the Passion flower, the perfect example of the Fibonacci series in nature.