A Rare Find in Madagascar Gets Its Own Genus

Tahina spectabilis (from the Latin for "spectacular") is a huge palm, with fan-shaped leaves as big as 15 feet across. As is the case with most palms, the leaves are arranged in a way that appears to minimize the amount they shade each other. So big is the green footprint of the few newly discovered specimens that people who know what they are looking for can spot them on Google Earth.

T. spectabilis is one of just a few species of "suicide palm" worldwide: trees that grow for decades, then throw every last bit of energy they have into an ultimately fatal reproductive frenzy. Some scientists call it "explosive" or "big bang" reproduction, but it is a slow-motion explosion, in which hundreds of thousands of flowers will bloom, attracting pollinators that, depending on the palm, may be beetles, bees or bats.

In all palms, those flowers become seed-laden fruits. Some, such as coconuts, have evolved a capacity to float far away. Most palms, including Tahina, produce fleshy fruits (in Tahina's case, about an inch across) that are eaten by birds and small mammals, which then disperse the seeds.

But that relatively limited capacity to spread their seeds raises one of the biggest mysteries about Tahina: How did it get to Madagascar? The three genera of palms most closely related to it, and with which Tahina must share a common ancestor, all live far away, in Central Asia, China and Thailand. Some suspect a seed may have rafted across a huge expanse of sea. Others wonder whether the ancestor originated on Madagascar, and some specimens rode northward on fragments of a continent that broke up more than 100 million years ago, portions of it drifting toward Asia.

"It just shows how little we know about these organisms, even those that are so big and showy," said Andrew Henderson, a curator at the New York Botanical Garden, who called the find "an amazing discovery, totally unexpected." No one knows how old Tahina must get before it flowers. Unlike most trees, palms do not have tree rings that allow scientists to check their age. That is because palms remain underground during their first years of life, until their trunks have reached their full adult girth. Only then do they grow skyward.

But scientists suspect that flowering events in Tahina are rare, because native residents say they have never before witnessed it.

That has helped energize an effort to preserve what is left of Tahina on Madagascar and to cultivate the seeds that have been collected.

Local people have constructed a stockade around the trees to protect them from cattle. And Kew is helping coordinate a program through which nearby farmers can sell the seeds to botanical gardens and researchers around the world.

"We'd really like to see the local people getting a good share of the profits for that," Baker said. "They are very much into this palm and very proud of it."