“The Irish potato (Solanum tuberosum) belongs to the order Solanaceae, or nightshade family, which also includes tobacco, tomato, egg-plant, pepper, etc. The edible portion, or tubers, being underground stems which have become enlarged through the accumulation of starch, are distinct from the roots. The sweet potato (Ipomoea Batatas) is related to the common morning-glory. The edible portion is simply an enlargement of the root, through accumulation of starch, and is not a tuber at all. Some varieties, generally those containing the largest amount of sugar, are commonly called ‘yams.’ This, however, is not strictly correct, as the true yam belongs to an entirely different family of plants.”