On the gorgeous islands of the Seychelles in the Indian Ocean grows a legendary palm, known for producing the largest and heaviest seeds in the world.

With their rather suggestive shape and impressive weight of about 25kg (55 lbs), the seeds of the double coconut, or coco-de-mer, measure up to half a metre long. This type of palm, Lodoicea maldivica, is the sole species in its family that’s endemic to the islands of Praslin and Curieuse in the Seychelles. Formerly, it was also found on the small islets of St Pierre, Chauve-Souris, and Ile Ronde (Round Island), all located near Praslin, but had become extinct there for a time until recently reintroduced.

According to legend, the double coconut has medicinal properties, but this remains unproven. Notwithstanding, the palm remains of high interest as an aesthetic wonder, with single nuts currently sold for £500-£2,000!

Unfortunately, similarly to many other plants the double coconut has been overharvested, and now there are only around 8,000 wild mature specimens remaining on just the two islands of Praslin and Curieuse. Therefore, the species is listed as Endangered on the IUCN Red List of Threatened Species.

It is no surprise, therefore, that the seeds of this precious palm growing in the wild – and in botanical gardens worldwide that have manged to grow them – are guarded carefully, sometimes even placed in a cage, to prevent poaching.

A female Coco de mer palm tree with some seeds in the growth, Praslin, Seychelles. Photo: WL~commonswiki

Some palms closely related to the double coconut also produce some of the world’s largest seeds, far larger than most other palm seeds – though much smaller than those of the double coconut (up to 10cm long).

Studying this amazing species could provide scientists the key to understanding the evolutionary forces that lead plants to produce very large seeds. Let’s hope we’ll know more about them soon!