Cross Sections of Yam (IMAGE) American Society of Agronomy Caption The edible yam tuber has a starchy, white flesh. Yams are a great source of fiber and potassium. Credit S. Yamanaka Usage Restrictions For use with this story only. 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.