Frailea schilinzkyana subsp. schilinzkyana sec. ???
- =Frailea friedrichii Buining & G.Moser in Succulenta (Netherlands) 50: 25. 1971 syn. sec. Hunt 2006
- =Frailea ignacionensis Buining & G.Moser in Succulenta (Netherlands) 50: 63. 1971 syn. sec. Hunt 2006
- =Frailea ybatense Buining & G.Moser in Succulenta (Netherlands) 50: 46. 1971 syn. sec. Hunt 2006