Aquatic Fern <i>Salvinia molesta</i> (IMAGE) University of Bonn Caption The aquatic fern <i>Salvinia molesta</i> traps underwater in a thin layer of air, which it can hold for many weeks. Credit © Prof. Dr. Wilhelm Barthlott/Uni Bonn Usage Restrictions This photo may be used with the press release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.