File collected hundreds of seeds from plants on a nearby beach, carefully labeling each seed with its ancestry. Then the two planted all the seeds in six different trays, sometimes planting only siblings nearby, and sometimes only strangers, and sometimes both. They started out with 384 plants (you've got to have fairly high numbers for credibility) but ended up with 332 after some of them died.
The trays were kept in a carefully controlled environment, and the plants were fed and watered exactly the same.
"We tried to treat everybody the same," Dudley said.
Just as the plants were about to flower, they were sacrificed in the name of science. They were dug up, their roots were analyzed, measured and weighed, allowing the scientists to see if there was any difference in the roots from plants growing with siblings, and plants growing with strangers.
"We found that kin groups allocated less to their fine root mass than did stranger groups when they competed below ground, indicating that these plants could discriminate relatives," the study concludes.
But what does it all mean? Should gardeners separate their seeds according to family history?
Maybe, but maybe not.
"We don't really know yet," Dudley said. If you want your plants to live peacefully side by side, maybe it's better to collect all the seeds from one "mom," as she puts it. On the other hand, there's lots to be said for biodiversity, and if the seeds come from different moms, the plants might have different growing habits, some sending their roots deeper than others, for example, and thus collecting nutrients from a different area.
So at this point, no one really knows what all this means. Except for one thing. Some plants, but probably not all, are a bit altruistic when it comes to taking care of their families. And they're much more interesting today than they were yesterday. And that's one of the really neat things about science.