oh some more things, re-reading that lovely "Fibonacci Flim Flam" essay I linked above, it turns out that:

sunflower seeds actually turn out to grow that way because the organism tries to pack the seeds as close as possible.

from this, if the close-packing manages to occur without disturbance, the golden ratio emerges--but if it is disturbed by anything (disease, damage, etc), the golden ratio becomes less accurate but the organism still continues packing the seeds as closely as possible.

that is how you can tell that the organism "tries" to realize a close packing and just happens to produce the golden ratio and sometimes Fibonacci numbers as a byproduct: if the process would have been based on the golden ratio instead, a disturbance would cause a spiral out of control with many empty patches.

finally, I almost forgot his (and nearly implied otherwise in my previous post), just the fact that the golden ratio occurs in a process or system does not mean that Fibonacci numbers are involved. there are many other number sequences of the same recurrence relationship as Fibonacci numbers that produce the same golden ratio. Lucas numbers, for example. However, the smaller ratios of those other sequences can be very different from the smaller ratios of the Fibonacci sequence (neither sequence approximates phi 0.618.. very closely for small numbers).

Counting seeds in sunflowers shows that some of them follow the Lucas sequence instead of Fibonacci. But again, you don't see those in the design books! (or sometimes you do but nobody bothers to check)