MORE than one in four of all flowering plants are under threat of extinction, according to an alarming report by scientists.

Many of nature's most colourful specimens could be lost to the world before scientists even discover them, say the researchers, whose work has been published in the journal Proceedings of the Royal Society B.

The results reflect similar global studies of other species groups by the International Union for the Conservation of Nature (IUCN), which estimates that one in five of all mammals, nearly one in three amphibians and one in eight birds are at risk of being wiped out.

Later this year the results of a huge global analysis by the Royal Botanic Gardens, in Kew, west London, of all the world's estimated 400,000 plants are due to be published by the IUCN as part of its mission to assess the state of all life on Earth. “[This year] marks the international year of biodiversity,” said Stuart Pimm, of Duke University in North Carolina, one of the authors of the report. “The focus of this celebration has often been on the species we know of, along with discussions on the unprecedented challenge of conserving this biodiversity in the face of threats such as habitat loss.

“However, by asking just how many species we will lose before they are even discovered, our study has revealed a figure that is truly alarming.” The researchers reviewed how many flowering plants — which make up most of the plant kingdom — exist.

The team calculated that on top of the existing “best estimate” of 352,282 flowering plants there are another 10-20 per cent, or 35,000-70,000, still to be officially discovered. The second stage of their research was to assess the level of threats from habitat loss.

— The Guardian, London