Many years ago a friend of mine asked me to taste a small bulbous root he had just dug out of his garden. To my surprise the raw tuber tasted rather like a crunchy juicy carrot/apple.
He gave me some to plant in my garden, and for the next few years I happily used the small tubers sliced raw in salads and cooked in mixtures with carrots and other vegetables. My friend called them 'yams'. This is what they looked like: