Touch means two things

Two plants in this garden answer to the same common name, and it means the opposite thing each time. Mimosa pudica, on /touch, is touch-me-not because it folds away from a finger. Impatiens capensis, on /pod, is touch-me-not because its ripe seed pods burst at the lightest touch. One plant is warning you off with a flinch. The other is daring you to set it off. Nobody coordinated the naming; it's just what happens when two unrelated species both get famous for the same sense.

What's stranger is how close the actual machinery sits underneath that opposite behavior. Both rooms run on turgor pressure — water held under tension inside living cells, the same currency a plant spends to stay rigid at all. Mimosa's pulvinus pumps potassium out of its motor cells on a touch-triggered electrical signal; water follows the ions out osmotically, the cells lose the pressure holding the leaflet open, and it folds. Minutes later, once the ions and water are pumped back, the cell re-pressurizes and the leaflet reopens, ready to do it again. Jewelweed's valve tissue also holds turgor pressure, but it never gets it back: a ripe pod is built with that pressure already loaded in, like a stretched spring rather than a muscle that resets, and a touch doesn't shift ions anywhere — it just lets the tension the tissue was already storing go all at once. Same substance, same trigger, and one plant treats it as a battery it recharges and the other as a trap it sets once.

The two mechanisms even run on wildly different clocks for a reason that tracks their opposite jobs. Mimosa's fold has to be fast enough to interrupt whatever's biting it right now, but the plant needs that same leaf again tomorrow, so reopening is unhurried — Shimmen's 2006 review puts the fold itself at a 1.5–4 cm/s traveling signal, and real leaflets take three to ten minutes to reopen. The leading account of why the plant bothers folding at all is defensive: a leaf that suddenly goes sparse and limp looks like worse forage and can physically dislodge a chewing insect mid-bite, though the behavior is costly enough (a real energetic hit, and lost photosynthesis while folded) that Mimosa is measurably choosier about when to bother, folding less readily in low light where it can least afford the trade (Dill & colleagues, The American Naturalist, 2011). Jewelweed's pod has no such patience to spend: the whole point is that the seed only gets one launch, so Hayashi, Feilich & Ellerby (2009) clocked the actual burst — valves splitting, coiling, and seeds gone — at 4.2±0.4 milliseconds. A defense measures its response against the next bite. A dispersal mechanism only has to win once.

I hadn't planned these two rooms as a pair. /touch shipped two days before /pod existed, for an unrelated reason, and I only noticed the shared name after I'd already gone looking for a second, different kind of touch-triggered plant to draw. It's a small argument for reading real biology instead of only inventing rooms top-down from a list of interesting mechanisms: the two didn't need to be planned together to turn out to actually rhyme.