Two rare seeds which floated 5,000 miles along the Amazon and across the Atlantic were found washed up on a Dorset beach.

Wildlife expert Steve Trewhella found two sea heart beans at Worbarrow Bay east of Lulworth on Friday.

The seeds, which are as large as conkers, are believed to have fallen from a monkey ladder vine in the Brazilian rainforest.

Mr Trewhella, a beachcomber and wildlife photographer, said: “They’re what we call drift seeds, they’re the seeds of tropical plants that drop into rivers.

“They’re designed to survive for a very long time in the water.

“They wash into the Atlantic from the Amazon and can spend up to 15 years drifting around in the sea and still be viable.

“I know people who have found them on beaches in Cornwall and grown them inside greenhouses.

“If they wash up on a beach in a different country they can still be grown. They have really hard shells and they’re deliberately buoyant so they don’t sink.”

He added: “Most wash up in Cornwall and Devon, where there’s nothing between us and America, but to find them in Dorset is quite rare.

“And to find two in the same day, that’s pretty special.

“I know people who have spent a lifetime looking for them and never found one.”

Mr Trewhella, 55, from Wareham, said the seeds have been found in the UK for hundreds of years if not longer.

He explained: “They’ve been used for all sorts of things in the past, for example, as talismans.

“When people started finding them, they didn’t know about other countries across the world. If you think about it we have only known about America for a few hundred years.”

Mr Trewhella, a regular beachcomber, said: “They’re really interesting when you think they could have been at sea for many years.

“We will be putting them with the other ones we found. We have got a bowlful from different places – there must be about 20 sea beans altogether which we have collected over 30 to 40 years.

“Once in a while you find half a dozen of these in North Cornwall, but that’s very rare.”

“For these to make their way across the Atlantic and down the English Channel to Dorset is quite unusual.”