Phyllotaxis
the spirals are counted, not admired
Concept

Orbit — where it appears

A closed cycle of divergences a stem circles without ever stopping, which is what a run that refuses to settle is doing. It is tens of degrees wide, so a mean over the top of such a run is a number no organ takes, and a stem in one at three hundred organs is still in one at twelve hundred.

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

The endpoint over four times the run: 60 of 63 do not move at all. One cell per wrecked run, dark where the divergence reported as its endpoint at 300 organs is the same divergence at 1200, warm where it moved. It moves on three of 63 runs, by a median of 0.0000 degrees and a worst of 0.0039. That worst is 128 times smaller than the 0.5 degrees at which two settled values are counted as one destination, and the movement has no sign — 1 up, 2 down. The short reading is precise about where a run finishes; it is silent about whether the run stays there.

Like with like

Seventeen wrecked runs settle when regrown to four times their length, and every one of them settles at the divergence the short run already reported. The endpoint moves by four thousandths of a degree at worst, which makes the short reading precise about where and silent about whether.

mechanism · Settling The same verdict at every length from 300 organs to 1200. The settling criterion applied to the first 300, 400, 600, 800, 1000, 1200 organs of each of the 63 regrown runs. It accepts 17 at every one of them and refuses 46 at every one, and not one run changes sides. A truncated twelve-hundred-organ run is the shorter run organ for organ, so this is a comparison of lengths rather than of growths. The slowest arrival in the whole set is 138 organs, so 140 is the measured requirement and 300 carries a factor of 2.1. The column drawn dark is 300 organs, where the verdict is 17 settled and 46 refused.

What a run length was hiding

The settling criterion returns an identical verdict on all sixty-three wrecked runs at every length from three hundred organs to twelve hundred, so run length explains nothing. What the sweep does find is that an endpoint is a mean over an orbit, and thirty-four refusers never come within a degree of their own reported endpoint.

mechanism · Settling

Named alongside it

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

Claim testingEndpointHonest limitsMeasurementNegative resultSettlingSettling criterionSummary statisticArtefactAttractorDestinationDrift

All concepts