Bright Cobblestone Lichen (Acarospora socialis) (IMAGE) Pensoft Publishers Caption The Bright Cobblestone Lichen (Acarospora socialis) fluoresces bright yellow under ultraviolet light on rocky outcrops near the Mars Desert Research Station. This fluorescence is one of many key characteristics useful in identifying lichen species. Credit Paul Sokoloff/Canadian Museum of Nature Usage Restrictions Credit must be given to the creator. License CC BY 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.