The East Texas Yamboree has a great Web page East Texas Yamboree
Where can you go and see several parades, lots of High School Queens, a bass fishing tournament a bunch of Marching High School bands, arts and crafts, throw in a little gospel and bluegrass music and top it off a barn dance? You have almost described one day of a four-day event called the "Yamboree" in Gilmer, Texas. One of the oldest festivals in Texas all dedicated to the lowly "Yam".
It all started in 1935, when every county in Texas was encouraged to come up with something to celebrate for the Texas Centennial in 1936. The folks in Gilmer and for that matter all of East Texas were hard pressed to find much to celebrate in the depths of depression era Texas. The only thing Upshur County could come up with was … "Yams". It had been a good cash crop for the county in the early 1930's. That was before the weevils came. The yams had been quarantine to the borders of the county and they had yams running out of their ears. That was the beginning of the "Yamboree".
This four-day event is held every October and is attended by about 100,000 each year. We were fortunate enough to be in East Texas the last day of "Yamboree". We setup our chairs right on the town square to watch the parade go by. The official parade didn't start for another hour, but the parade I enjoy most is the parade of people there to watch the parade. There were young people, old people, and children there were skinny people and not so skinny people. There were couples of all ages and sizes. Once again it was proven that "there is lid for every pot.'
The whole day I was there taken in all the fanfare, turkey legs and music I ask everyone I met, "What's the difference between a "Yam" and a "Sweet Potato"? No one could tell me. Not that it is that important but I wanted to know. As I kept getting blank stares I came to realize that the real reason that they call them "Yams" in Upshur County is it is easy to turn "Yam" into "Yamboree" , but sweet potato? Maybe "Sweet potato 'boree". It just doesn't have the same zing does it?
I had to go the Department of Agriculture for my answer and here it is:
"Several decades ago, when orange-fleshed sweet potatos were introduced in the southern United States, producers and shippers desired to distinguish them from the more traditional, white-fleshed types. The African word nyami, referring to the starchy, edible root of the Dioscorea genus of plants, was adopted in its English form, yam. Yams in the U.S. are actually sweet potatos with relatively moist texture and orange flesh. Although the terms are generally used interchangeably, the U.S. Department of Agriculture requires that the label "yam" always be accompanied by "sweet potato.""
So there's your answer. In short in the U S of A there is no difference. Don't say you never learned something from Texas Bob.