These are waxy potatoes.
No longer in commercial production.
Garnet Chili Potatoes were developed in 1853 by the Reverend Chauncy E. Goodrich, an Anglican minister in New York State. One parent potato was the Rough Purple Chili potato, which he had obtained from contacts in Chile. At the time, potatoes in North America were suffering from blight; Goodrich’s theory was that stock had grown weak through cultivation and selection, and that re-introducing more vigorous stock from South America would help.
Lindquist, Craig. “Garnet Chili Potatoes” in “Vegetables of Interest.” 25 August 2007. Retrieved August 2009 from http://vegetablesofinterest.typepad.com/vegetablesofinterest/2007/08/garnet-chili-po.html