Ancient palm tree studied for two centuries in Edinburgh was wrongly identified

Botanists researching Scotland's oldest palm tree have discovered it’s not the species they thought it was – more than 200 years after it was wrongly ‘identified’ and labelled.

By George Mair
Friday, 13th May 2022, 4:55 am

The much-loved palm, nurtured for nearly 230 years at the Royal Botanic Garden Edinburgh (RBGE), has been unveiled as a botanical enigma.

Nearly eight months after it was felled to make way for a major restoration project in its Tropical Palm House, experts conducting due diligence have now determined the 60 ft treasure was not an example of the endangered Sabal bermudana.

In a further twist if, as is now suspected, the long-lived specimen is Sabal mexicana, this was a new species still to be described to science for around 40 years after it went on display in the 1790s.

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The ancient palm's misidentification was discovered after it outgrew its home at the Botanics Pic: Lynsey Wilson RBGE

Sadie Barber, RBGE's Research Collections Manager, said: "The palm we had for 200 years isn’t what we thought it was.

"We now know that our Sabal is not in fact Sabal bermudana. It is most likely Sabal mexicana although only with flowers or DNA sequencing will we know for sure.

"This doesn’t make the palm any less important in terms of its historic relationship with RBGE, but it does shift the focus away from Bermuda."

The palm was shipped to the Port of Leith via Germany in the 1790s and originally grew in the RBGE's former site in Leith Walk until the entire plant collection was transported to its current home in Inverleith in the 1820s.Thousands of plants were removed from the A-Listed palm houses last year to allow construction to begin on the ambitious Edinburgh Biomes project to safeguard the Garden as a global resource for future generations.

The historic Sabal palm was dismantled by experts, with seedlings cultivated so that visitors can watch its progeny grow "for another 200 years".

It was dissected to create a lasting Herbarium specimen and a detailed botanical illustration was completed along with close-up photography in order to confirm the identity and create a free resource for scientists and other interested parties now and in the future.

During the documentation procedures, Scott Zona, the US-based leading authority on the Sabal family, highlighted some subtle differences in the biology of various species.

RBGE tropical botanist Dr Axel Dalberg Poulsen said: "Using Scott's elaborate monograph of the 15 known species in the genus Sabal, I narrowed it down to three possible species.

"Only last week, Scott looked at our evidence and now we have a clearer idea of the true identity of the flagship palm of the Royal Botanic Garden Edinburgh.

"It is not Sabal bermudana as the label said for a very long time but quite possibly Sabal mexicana.

"The German botanist CFP von Martius only described Sabal mexicana as a species in 1838. Thus, until then, the palm at the Botanics was actually a new species."

Full verification can only be achieved through DNA sequencing or once flowers of its progeny are collected and examined, which could take several decades until the young palms are mature.