What is the difference between yams and sweet potatoes? There is such a thing as sweet potato pie, but I've never heard of yam pie.

Yams and sweet potatoes are both tubers that are roots of tropical vines and both are vegetables.

True yams grow larger than sweet potatoes. There are more than 50 varieties of yams, and the largest can grow up to 7 feet long and weigh as much as 125 pounds.

Sweet potatoes can be identified by the shape of their ends, which taper to somewhat of a point.

Sweet potatoes are classified in two categories for retail purposes. The first variety is thin, with light yellow skin; its flesh is not very sweet. The other variety has Halloween-orange flesh, is a lot sweeter, and its much thicker skin ranges from light to dark orange or even light red.