A TINY species of moss which was thought to have been extinct for more than three decades has been discovered in West Devon. The exciting discovery was made last week at Roadford Lake where minute Millimetre Moss (micromitriam tenerum) was found at the reservoir. Millimetre Moss grows on mud beside ponds and lakes that is exposed by seasonal falls in water levels. It was last seen in Britain in 1971 on Anglesey and during the 1960s in West Sussex, but water levels have been high at the lakes involved for many years, and the species was therefore feared extinct in Britain. The find came during research on rare mosses and liverworts carried out by Dr David Holyoak for ERCCIS (Environmental Records Centre for Cornwall and the Isles of Scilly) funded by the Environment Agency. Robert Wood, of the Environment Agency, said: ?Millimetre Moss is a tiny fast-growing plant, well adapted to making the most of mud exposed to the air for just a few months of each year. ?Spherical capsules containing its spores begin to appear within weeks after the leaf rosettes grow. ?It is thought that the little living spores may survive in mud for several years, awaiting another dry season when the cycle of growth and reproduction can be repeated. ?Although it would be easy to dismiss this moss as tiny and insignificant, every discovery of life thought to be extinct is an exciting one, and an important addition to the jigsaw of our biodiversity.? The tiny moss is given special protection under the Wildlife and Countryside Act, listed as ?critically endangered? in the Bryophyte Red Data Book, and treated as a priority for conservation under the UK Biodiversity Action Plan (UKBAP). The Environment Agency is already responsible for work under the UKBAP on other mosses that grow in seasonally exposed late mud, in partnership with Plantlife International. The varying water levels and unpolluted water needed by Millimetre Moss should be easy to maintain at Roadford Lake, where it has been found at three locations. Further surveys are now planned to check whether it grows undetected beside other reservoirs in Devon and Cornwall.