Architectural Pottery (AP) in the shape of what is known as "the tire". This beautiful pot is in great vintage condition without any chips are cracks. The stamp is on the inside of the pot and was hard to photograph, so we did a rubbing, shown in the photos. It reads Architectural Pottery and Made in USA in the center. 

17"in dia x 11"t 

Architectural Pottery " Tire" by John Follis