Scientists are piecing together how this palm, called the coco de mer, manages such an extreme feat on poor soil. New research suggests the tree has turned its leaves into a rain-harvesting system that feeds the parent and its young.
The giant seed of the coco de mer
The coco de mer comes from a rare palm that grows naturally only in the Seychelles, where its seeds can reach about half a meter wide. Most of us are used to pumpkin or sunflower seeds, so how do you picture one this size? In a recent BBC Wildlife report, the seeds were described as the biggest on the planet.
A seed is the plant’s starter kit, storing food and genetic instructions for the next generation. Here the starter pack is supersized, giving the young palm energy to push roots into rocky ground and survive years in the shade beneath its parent.
A palm that funnels rain like a gutter
Ecologist Christopher Kaiser-Bunbury at the Technical University of Darmstadt found that coco de mer leaves act like gutters that catch rainfall and channel it down the trunk, like rain running off a roof. As the water flows, it sweeps up fallen pollen, animal droppings, and other debris rich in phosphorus, an important plant nutrient.
This mix soaks into the soil at the base of the tree, right where the giant seeds land and germinate. Scientists describe this as a kind of “parental care,” since the palm effectively fertilizes the nursery under its own crown.
Why evolution favors such huge seeds
On isolated islands without many large animals, seeds do not travel far and end up sprouting close together. Studies of island plants suggest that species in these conditions tend to evolve larger seeds that fuel sturdier seedlings.
Big seeds are expensive to produce, so each tree makes fewer of them, but each one has a better chance of surviving tough competition and poor soil. Seen together, the new findings suggest the coco de mer’s seeds are not a botanical oddity but a survival strategy for island life.
The main study has been published on the journal New Phytologist.
