From the La Rioja province of Argentina, Echinopsis fatimensis is a tighly spined globular cacti to 3 inches tall and 2-1/2 around. It sometimes offsets. Formally in the Lobivia and Rebutia genera, Echinopsis fatimensis was moved to Echinopsis in 1931. Why I dont' know, the pics I've seen of the normal plant and flower look more Rebutia-like to me. It is named for the Sierra Fatima mountains where it is found.
     I don't have a normal one but picked up this beautiful purple crest at Home Depot a while back. There was another that had some normal growth on it. I should have gotten both, I probably could have rooted the normals as cuttings.