Physcomitrella patens (IMAGE) Washington University in St. Louis Caption The moss Physcomitrella patens is often used as a model organism for water stress studies. Credit David Cove Usage Restrictions None 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.