Ponderosa Cellular Structure (IMAGE) The University of Montana Caption This is an image of a pit membrane, the cellular structure linked to slow growth, drought resistance and longevity in ponderosa pines. Credit Beth Roskilly 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.