Palm surprise

As our lists of well-monitored species worldwide show increasing numbers of those in decline and under threat, it is a treat for researchers to learn of the discovery of a new species — even more so when it is large, showy and appears to be quite distinct from its nearest known relatives. That was the news last month when researchers reported a new species of palm in Madagascar. It was so distinctive that researchers assigned it to a new genus and named it Tahina spectablis. The palm has a trunk which reaches 18 metres and fan leaves up to five metres in diameter — the largest palm to have been found in Madagascar. But it is its life cycle that has created particular interest: it appears to flower just once at the end of its life in a spectacular show of blossom, nectar and seed before it dies. It’s a strategy that is used by several monocotyledons but so far has not been observed amongst the palm species, which more usually flower and fruit at regular stages throughout their lives. The palm was discovered by Xavier Metz, a French manager of a local cashew nut plantation. While he and his family were walking in a remote region of north-west Madagascar, they came across the palm with its distinctive pyramidal flowering structure towering above the top of the palm’s leaves. He sent photographs to John Dransfield, a palm specialist and honorary fellow at Kew Gardens, who was excited at the images of the tree. Leaf fragments were sent to Kew for DNA analysis, which confirmed that the palm was not just a new species but a new genus too. The new genus is linked to just three others; one occurring in Arabia, Iran, Afghanistan and Pakistan, another in southern Thailand and the third in Vietnam and southern China. “The tribe has an extraordinary distribution and it is very difficult with current knowledge to explain how it could ever have reached Madagascar,” says Dransfield. With an estimated population of less than 100, the new palm presents significant challenges to conservationists. The palm grows in deep fertile soil at the foot of a limestone outcrop that is dry for eight months of the year but then subject to seasonal flooding. With flowering and fruiting such a rare, terminal occurrence, the plant presents additional headaches for botanists. “The palm highlights the conservation challenges for all the palms in Madagascar, many of which are seriously threatened with extinction,” says Dransfield. Dransfield has held talks with Metz and local people in an effort to protect the palm and help the local community raise money by selling seed to botanic gardens and growers around the world.