Roots

Every plant on this site is drawn from the soil line up. The daily specimen, the greenhouse, the weeds, the whole margin of sketches — all of them stop at the ground. That's the honest habit of a garden drawn from above: you see the half that reaches for light and never the half that does the harder work in the dark. This room draws the other half, and it corrects the thing almost everyone believes about it.

The folk picture is that a root seeks water — that it smells moisture across the soil and turns to grow toward it, the way a shoot bends toward a window. Roots barely do that. What they actually do is stranger and more local: a root branches a new side-root only on the face that is already touching water, and leaves the dry face bare. Bao and colleagues named it hydropatterning in 2014: lateral roots form on the wet side of the main root and are suppressed on the air side, positioned before a branch has even begun, by the growth hormone auxin gathering where the water is. Not a search. A vote taken cell by cell around the root's own circumference, and the same trick works in thale cress, maize, and rice alike.

So: a patch of moist soil you can move. Drag it to either side of the taproot, or use the buttons. New roots break out only where the water meets the root, and only on that side. Watch the taproot itself while you do it — it stays its course straight down and never once leans toward the water. That's the whole point: the branches know which side is wet; the root as a whole doesn't go looking.

Honest gaps. Real hydropatterning plays out over days, on a root tip that is also lengthening; this patch acts in a second on a root that holds still, so you can see the rule instead of waiting for it. Real roots carry a mild, genuine hydrotropism too — a slow bend toward moisture, run by different machinery — which this room leaves out on purpose, because the surprising, load-bearing fact is the branching one, and drawing both at once would blur exactly the thing worth seeing. And a root once branched doesn't un-branch when the soil around it dries, so laterals here stay put once they've formed; only Drain clears them.

Nothing here reads a date, calls plant.js, or rolls its rng(). The small waver in each side-root's length and angle is plain Math.random(), decided once as it emerges and never re-rolled — the same untethered jitter /pod and /pulse already allow themselves, since nothing drawn here is a fact the garden claims is reproducible.

Sources: Bao, Aggarwal, Robbins, Sturrock, Thompson, Tan, Tham, Duan, Rodriguez, Vernoux, Mooney, Bennett & Dinneny, “Plant roots use a patterning mechanism to position lateral root branches toward available water,” PNAS 111(25):9319–9324, 2014, for hydropatterning and its auxin basis; Robbins & Dinneny, “Growth is required for perception of water availability to pattern root branches in plants,” PNAS 115(4):E822–E831, 2018, for the finding that the sensing happens in the growing tip.