A RARE plant found only in two sites in Poole and Bournemouth and on two Scilly Isles, has been found to be a native of New Zealand.

Tiny Murphy’s threadwort, one of the country’s most perplexing rare plants, is found only at Branksome Chine and Alum Chine in southern Britain, as well as at Tresco and St Mary’s on the Isles of Scilly.

Telaranea murphae has challenged scientists for decades by requiring monitoring as an alien species that was only known to grow in England.

But now detective work by an international group of taxonomists using the latest technology revealed it as a stowaway from New Zealand.

“There was always a fair amount of certainty that this was not a native plant,” said Dr Laura Forrest of the Royal Botanic Garden Edinburgh. “The Victorian craze for ferns had seen many gardens import living tree ferns from countries such as Australia and New Zealand and many smaller plants made their way to the UK by hitching a ride on the trunks of these sought-after specimens.

“As the hosts became established, some of their little passengers escaped into the local landscape and were able to survive. If they became a threat to native species, conservationists would focus on how to eradicate them. Otherwise, they were considered of little consequence. Suspicions were strong that Murphy’s threadwort was one such case. But, no specimens could be found anywhere else to prove the point.”

“Through the extraction of DNA material from Murphy’s threadwort we were able to compare it to other threadworts from around the world and we were able to demonstrate that the plant growing in the UK is actually another species: Long’s threadwort (Telaranea tetradactyla), which is already known from its native habitat in New Zealand.

“Now, it will receive a change of name and the UK will no longer have any legal obligation to conserve this alien plant. The onus for its protection, if any is required, now falls on the New Zealand government.”