I didn’t realize this until recently, but apparently if a company or store labels sweet potatoes as “yams,” they can get in trouble with the United States Department of Agriculture, which views sweet potato (Ipomoea batatas) and yams (Dioscorea spp.) as distinct commodities. So if you feel a product label (or bin label at the store) gets the identification wrong, just snap a photograph and email to the USDA’s Misbranding and Misrepresentation Office. The responding officer then gets in touch with the company or store and ask the labels be updated. Of course, it’s probably often true that labels are just inadvertently misleading, such as in stores where produce managers don’t know what a yam is — the USDA would never fine those individuals, I suspect. If enough people reported these instances, the confusion over yams and sweet potatoes would drop, and fast. Less confusion is always a good goal, but this getting ridding of the “yam” slang would be extra good because it makes life a tad safer for those with sweet potato allergies (they might eat one if it is labelled “yam”).