The healing secrets of the fungi, asco mycetes, have now put it at the centre of a custody battle between British scientists and the Thai government.
The Biotec Institute, part of Thailand's Ministry of Science, says Portsmouth University is guilty of "bio-piracy" because it failed to return the 200 specimens, despite giving an undertaking that it would.
It also claims that the university has breached the 1992 Rio Convention on biodiversity, which forbids the removal of specimens from their country of origin without permission.
The university is refusing to release the marine fungi, which could provide a cure for cancer and were collected by university staff on a research trip to Thailand. There has been an angry exchange of letters between it and the institute, which is now threatening legal action.
The specimens were collected by Professor Gareth Jones, then employed by the university, for a company that was funding research into possible treatments using fungi. He was part of a team from Portsmouth, a world leader in fungi research, looking into the chemical properties that could be used to cure deadly diseases.
In 1994 he helped to discover a chemical in a marine fungus from the coast of Malaysia which killed leukaemia cells. The find was the result of a world-wide drive to collect and screen some of the 1.5 million species of fungi for new drugs.
His team removed the asco mycetes fungi from floating wood, mangrove swamps and coastal waters. It was taken to Portsmouth for storage because there were then no adequate facilities in Thailand. However, the Thai authorities demanded the return of the fungi when Professor Jones joined the Biotec Institute.
Nigel Hywel-Jones, the institute's head of mycology, is prepared for a long fight to win back the fungi. His concern is that Thailand will not benefit from royalties if the fungi are sold to a pharmaceutical firm.
"I'm going to fight like hell to get the specimens back," Dr Hywel-Jones said. "As far as we are concerned, they have breached the Rio Convention, which was set up to prevent cases like this. It clearly states that specimens belong to the country of origin.
"Nothing was written down on paper but it was understood the fungi would be returned. Academics have trusted each other in the past.
"These fungi are valuable for research into herpes, malaria and tuberculosis, which are a problem in Thailand. Instead, Portsmouth is using them for its own research."
However, the university, which holds more than 6,000 species of fungi, says the real reason for the fungi dispute is "academic pique". It emphasises that the fungi are being properly looked after in their laboratories until ownership is resolved and have not been sold to science.
A spokesman said: "We are not in a position to give them back to the Thai government because they are not ours to give. They could belong to the company we had the contract with.
"As far as we are concerned, we have not broken the Rio agreement because they are not the only specimens of their kind in the world."Reuse content