13 Rice Varieities over 15 Million Years (IMAGE) Cold Spring Harbor Laboratory Caption Top: Geographic distribution of 13 rice varieties compared in the new study by Ware and colleagues. Dashed red lin shows limits of rice cultivation. Bottom: A tree showing the evolutionary relationship of 13 rice varieties compared in the new study, spanning a period of 15 million years Credit Ware Lab, CSHL 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.