Fibonacci and pineapples

The Fibonacci sequence is found in the strangest of places. Take pineapples for example. The number of spiral rows of fruitlets (eyes) in pineapples was study as early as 1933 in an article by Linford [1] published in Pineapple Quarterly, however no reference was made to Fibonacci numbers. In a follow-up study by Onderdonk [2] in 1970 it was found that the majority of pineapples had 8-13-21 rows of fruitlets, with a few smaller ones at 5-8-13. It was suggested that a pineapple with more fruitlets for a given size would have a finer texture, and it was hoped that a pineapple with 13-21-34 rows could be found, however Onderdonk never found any pineapples exhibiting such a pattern. In general, pineapples have three series of spirals, derived from the roughly hexagonal pattern of its fruitlets, or scales.

Here is an example of the hexagonal scale patterns found on a pineapple.

Further reading:

1. Linford, M.B., “Fruit quality studies II. Eye number and eye weight”, Pineapple Quarterly, 3, pp.185-188 (1933)
2. Onderdonk, P.B., “Pineapples and Fibonacci numbers”, The Fibonacci Quarterly, 8(5), pp.507-508 (1970)