Valley of the timeflowers

The American nightshades are a particularly ingenious family of plants. Each one has its own mechanism to avoid being eaten: the potatoes have solanine, the chiles have capsaicin, the tomatoes have nicotine, and so on. In this way, they punish all the bugs and beasts that would gobble them up. Deterrence is a family business for the nightshades, and a stunningly effective one. Yet their successes are not perfect. Indeed, despite their ingenuity, the American nightshades all carry a peculiar air of noble tragedy: for every perfect defense, there is always a fatal flaw. If you need proof, just consider papas con chile, that delicious dish of crispy fried potatoes stirred with chili peppers in a fresh tomato sauce.

In my view, no plant better demonstrates the tragic brilliance of the American nightshade family than Solanum nepenthes, the forgetful sunberry. Here is a plant that, like its cousins, was gifted with a powerful defensive capability. Instead of chemical deterrents, however, it used an altogether more peculiar and fantastical method: obliviation. Anything that ate the plant would simply cease to exist. I don't mean "die"—any toxic nightshade can do that. No, these sunberry plants simply erased their ill-fated devourers from history, retroactively wiping them out at the moment of their birth. (The specific mechanism, for the biologically interested, involved tampering with the predator's originating sperm cell. By disrupting proteins in the sperm cell's arcosome, the plant could prevent that cell from fertilizing and hence prevent the predator from being born at all; instead, some other sperm cell would usually succeed in its place. As to the greater mystery of how the plant tampers across such wide distances in space and time, I believe no one yet knows.)

Consider, for a moment, the extraordinary selective pressure of obliviation: it can veto whole swaths of a generation without any apparent time passing. Indeed, the only stable timeline is one in which no sunberry plant has ever been eaten. Thus animals avoided these plants just as they avoided plants that had poisoned them for generations. Mimic plants co-opted their appearance and smell. Some undeterrable animals went inexplicably sterile and died out. Nothing ever ate a single sunberry except for certain blight molds which were, after all, immune to their peculiar effect. For a time, the sunberries flourished.

The trouble arose when humans first arrived. To understand what happened, recall the butterfly effect: even the smallest change to the past will ripple outward, disrupting the whole course of the future from weather patterns to human events. Because our genetic identities are determined by a precarious lottery at conception, for example, even changing a single molecule in the past will have knock-on effects that reroll the identities of everyone born more than, say, a week afterward. The next generation will then be made of entirely different people than it used to be, and the changes will compound from there. Thus every time a sunberry plant erased a predator, it incidentally changed many of the subsequent conditions and accidents throughout the world.

In short, through the butterfly effect, Solanum nepenthes had quite a lot of indirect influence on the fates surrounding its would-be predators. Sometimes a human who ate a sunberry plant would be rewritten as someone who happened to get crushed by a falling tree before they could ever try eating a sunberry. Evolution, you see, is ruthlessly open minded and not especially interested in happily-ever-afters. Any fate that prevents the plant from being eaten will pass the test. Any person who, however indirectly, causes more plants to be eaten is likely to be altered by obliviation. Think of it like a mutagenic effect of getting too close to Solanum nepenthes.

Now human beings are rather intransigently curious, as a rule. By the time humans arrived, they already presented a huge threat to these plants who insisted on never being eaten even once. It was too late to send the humans all away; obliviation can only rewrite history starting from the predator's birth. And so came the millionfold flashes of predation and rewriting which need a god's-eye view to describe. I am sure that Solanum nepenthes domesticated some humans directly, saddling them with aversions and maladies. But when the timeline finally settled, this was not, in the end, the most adaptive solution. (Perhaps human minds have too many moving parts.) At some point, one Solanum nepenthes plant, retaliating against a child who had crammed a fistful of flowers into its mouth, inadvertenly spawned a version of events where the previous summer was especially dry. One stray lightning strike, and the whole meadow caught fire. The plant and all of its dry, dry neighbors were set alight. Alas, it turns out that being burned to ash is an especially effective way to keep anyone from eating you—doubly so, because once this fate is written by one sunberry plant, its charred neighbors are in no position to rewrite it.

In this way, great numbers of plants were very suddenly wiped out through floods, fire, blight, and other natural disasters in the decades preceding the first humans arriving on the American continent. None have been found in the places humans have settled. Few people know they existed, and even fewer hold out hope that extant plants will ever be found.

Let me end on a culinary note. A philosopher friend of mine has suggested that sunberry plants, due to their obliterating defense mechanism, can never be tasted and therefore in some ostensibly interesting sense must have no defined taste. Through long hours in the greenhouse, I've mulled over this curious idea and frankly, I think it's the unfortunate philosopher who has no taste. In my personal experience, chargrilled Solanum nepenthes tubers have a delicious savory flavor. I'm always quite careful to avoid the undercooked ones—but then again, it figures I would be.