Grass Stomata (image) Carnegie Institution for Science Share Print E-Mail Caption This image shows the four-celled stomata found in grasses, featuring two dumbbell-shaped guard cells surrounded by two subsidiary cells. Scientists attribute the tremendous success of grasses to this valve structure, which is capable of more-sensitive and precise responsiveness to the environment and likely enhances the plant's performance, particularly in high temperatures or drought conditions. Credit Dominique Bergmann and Michael Raissig Usage Restrictions With credit Share Print E-Mail 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.