This chapter introduces the observation of Fibonacci phyllotaxis: that the arrangement of leaves, seeds, or scales in some plants can come in spirals, and the count of these spirals is often a Fibonacci number. There are many accessible example of Fibonacci phyllotaxis: perhaps the most robustly repeatable observation for city-dwellers is to buy a pineapple. However for most species, including the pineapple, large-scale scientific data is surprisingly sparse on the exact prevalence of different kinds of patterns, and especially on the ways in which patterns fail to be Fibonacci. An argument of this book is that it is when patterns fail to be Fibonacci that they are most informative for model testing, and we will return to this in the second half of the book.