Phyllotaxis
the spirals are counted, not admired
Concept

Feedback — where it appears

An arrangement in which a placement affects the placements that follow it, so an error is passed along rather than staying where it was made.

Named by 3 essays across 2 fields — each of them below, with the objects they name alongside it.

rise 0.032counted 3/5angles say 336912150.5rise 0.013counted 5/8angles say 55101520250.5rise 0.005counted 8/13angles say 8816240.5151015202530lag, in internodescorrelation between a divergence and the one that many internodes later3 runs per rise · 320 internodes eachthe counter is never shown a position

The order carries the count

Take the divergence angles off a stem, throw away every coordinate, and autocorrelate what is left. The result is periodic at the smaller parastichy number — peaks at it and at every multiple of it. A list of angles, with no picture and no position in it, carries the spiral count.

cylinder · sequence -0.50000.500100200300nodes per rung of the ladder — how slowly the shoot climbscorrelation between one divergence and the nextthe rise held fixed — -0.68no noise · 185, 254, 323, 438, 553, 922, 1474 nodesthe threshold is in the rate, not the rule

The memory was the rise

The previous phase measured a lag-one correlation of 0.54 in a noiseless divergence sequence and called it the sequence's own memory. Hold the rise fixed and there is no sequence at all — every angle identical — and under a disturbance the correlation is negative. The 0.54 belongs to the pattern chasing an equilibrium that is moving under it.

cylinder · sequence -0.50000.500100200300nodes per rung of the ladder — how slowly the shoot climbscorrelation between one divergence and the nextthe rise held fixed — -0.68no noise · 185, 254, 323, 438, 553, 922, 1474 nodesthe threshold is in the rate, not the rule

A shoot too fast to remember

Sweep the rate at which a stem climbs the ladder and the correlation between one divergence and the next changes sign — negative below about fifty-five nodes per rung, positive above it, with the flip inside one step of the grid. The instrument the previous phase proposed is unavailable on a fast shoot, and nothing said so.

emergence · rising

Named alongside it

The objects these essays reach for when they reach for this one.

AutocorrelationCylinderDivergence angleEnsembleEquilibriumMeasurementNoiseThe placement ruleRiseSelf correctionSummary statisticTracking

All concepts