In response to the comments of my last post, I (Jared) am forced to write a rebuttal on my own behalf.
Firstly, while many may believe yams to be orange and soft when cooked, they are actually most often darker than a regular potato (sometimes almost black). The fleshy parts of the inside vary in color depending on the outside darkness, but are almost never an orange tint. They can even have a purple color. They are also actually much longer than what we in the U.S. think yams are. Here is a picture as an example.
Secondly, there are 3 major varieties of sweet potatoes grown in the United States. The majority are grown in the South, somewhere down in the bayou. One variety is nearly the exact same consistency and color of a regular potato. Another has a slightly yellow color, and the third is orange. Here is a picture of traditional sweet potatoes.
Now you might be telling yourself, "Silly Jared, those are yams, not sweet potatoes." This brings me to my last point. In the South, and other areas, the orange variety of sweet potatoes are commonly referred to as "yams" (even though they actually are not). Because of this, many recipes, cooks, stores, common folk, dogs, cats, and even children refer to them as "yams". So when you go to the grocery store and buy a "yam" you are actually buying a sweet potato. Hence, my post that yams and sweet potatoes are one and the same.
My theory is people started calling them by their real name instead of yams because everyone knows that yams are disgusting, but when you say it is a sweet potato it doesn't sound too bad. Sweet potato fries are delicious, but you might as well call them "yam fries".... mmmmmmmm.
HA, put that in your pipe and smoke it!