Lucas numbers — where it appears
Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.
Fibonacci is a branch, not a law
Fibonacci counts come from one branch of the model. The Lucas branch — which the same rule reaches at a different growth rate — gives 47 and 76, and neither is a Fibonacci number. The sequence is a consequence of an angle rather than a property of plants.
Every family but two is a sum
A seed head has six spiral families and everybody reports two. That looks like a convention hiding information and it is the opposite — every family but the two smallest is the sum of two others, so a third count is a prediction rather than a measurement, and a check that catches a wrong pair.
Named alongside it
The objects these essays reach for when they reach for this one.
Continued fractionFibonacciAttractorCounting blindBranchContinued fraction convergentConvergentsDelaunayDivergence angleGolden angleφ, the golden ratioLattice