Fibonacci in Bloom — why a sunflower's spirals count 34 and 55

Fibonacci in Bloom

Why a sunflower packs its seeds at one exact angle — and out fall spiral counts of 34 and 55, never anything in between.

A · Specimen

Each is the same rule at a different size — bigger heads climb higher up the Fibonacci ladder.

B · Divergence angle

Turn between seeds—

A rational fraction p/q of a turn lines the seeds into q spokes. The golden angle is the least rational turn there is — so they never line up.

Florets

Seeds in the head—

Count the spirals

Tally one family arm by arm — the running count lands on a Fibonacci number every time.

Show

angle—

of a turn—

florets—

spiral arms—

ratio—

Spiral arms

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Phyllotaxis · seeds placed by the golden angle